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MMBase: An open-source content management system



MMBase is an open-source content management system (CMS) with portal functionality, originally created by the Dutch public broadcaster VPRO. MMBase, which is particularly suited for multimedia environments, is based on the concept of presenting objects on different channels. The system is highly platform-independent and has adopted standards such as Java™, XML (Extensible Markup Language), J2EE™ (Java™ 2 Enterprise Edition) and JDBC™. Initially used only by public broadcasters, MMBase has been adopted by a growing number of organizations. This paper presents the history of MMBase, introduces its community of users, and discusses its architecture, focusing on the innovative technical process underlying MMBase and its organizational structure. We identify and discuss three challenges facing the user community: the need to motivate and organize both users and developers to contribute to the development of MMBase, the need to make the software modular, and the need for more and better documentation of the MMBase core and its component packages.
MMBase: An open-source
content management system
J. Becking
S. Course
G. van Enk
H.T. Hangyi
J.J.M. Lahaye
D. Ockeloen
R. Peters
H. Rosbergen
R. van Wendel de Joode
MMBase is an open-source content management system (CMS) with portal
functionality, originally created by the Dutch public broadcaster VPRO. MMBase, which
is particularly suited for multimedia environments, is based on the concept of
presenting objects on different channels. The system is highly platform-independent
and has adopted standards such as Javae, XML (Extensible Markup Language), J2EEe
(Javae2 Enterprise Edition) and JDBCe. Initially used only by public broadcasters,
MMBase has been adopted by a growing number of organizations. This paper presents
the history of MMBase, introduces its community of users, and discusses its
architecture, focusing on the innovative technical process underlying MMBase and its
organizational structure. We identify and discuss three challenges facing the user
community: the need to motivate and organize both users and developers to
contribute to the development of MMBase, the need to make the software modular,
and the need for more and better documentation of the MMBase core and its
component packages.
MMBase is an open-source content management
system (CMS), maintained and improved by the
MMBase community and initially developed at
VPRO, a Dutch public broadcasting organization.
MMBase is a widely adopted open-source solution in
the Netherlands. Its growing user base includes a
number of well-known and highly respected orga-
nizations: Dutch government departments, the city
of Amsterdam, and broadcasters like VPRO, EO
(Evangelical Broadcasting Organization), Radio 538,
Dutch Internet organizations for education, and
many cultural organizations. Recently, there has
been a growing interest in MMBase from markets
outside of the Netherlands: its adoption by Vodafone
is probably the best example.
CMSes typically separate the concerns of content,
application logic, and visual make-up.
In addition
to these characteristics, MMBase shares a number of
characteristics with enterprise content management
(ECM) systems. An ECM system is different from
traditional CMSes in that it ‘‘integrate[s] information
(content) from different sources, form[s] it into a
collection (compound content), provide[s] it to
users and applications, and add[s] value to the
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represented information.’’
ECM systems provide
the same functionality as traditional content man-
agement systems, but add two distinct features:
&MMBase is continuously
evolving &
content infrastructure, which allows solution appli-
cations to be built without a large system integration
effort, and content integration, which consolidates
content from various sources to make it easily
accessible to a network of users.
The combination of a number of characteristics
makes MMBase unique. MMBase is focused on
structured content. This represents a difference
when compared to a CMS like IBM Content
Manager. The latter has the ability to ‘‘manage
nontraditional, heterogeneous, unstructured data.’’
MMBase lacks such functionality and must be
combined with other systems to store and retrieve
other types of data and content. Therefore, MMBase
should be characterized as a CMS and not as an ECM
MMBase is platform- and database-independent.
Many of the bigger companies are highly heteroge-
neous: they have adopted a wide variety of data-
bases and hardware platforms. MMBase supports
this heterogeneity, as it can be used on most of the
available platforms (UNIX**, Linux**, and Micro-
soft Windows**). Platform independence in
MMBase is achieved through Java**,
and it can be
used with many commonly used databases (e.g.,
Informix**, DB2*, Oracle**, PostgreSQL**,
MySQL**). Heterogeneity is a significant advantage,
as it allows companies to use MMBase while
maintaining low operating costs by focusing on a
single operating system and database.
MMBase strictly upholds the multitier architecture
of Java’s enterprise edition. Because data, applica-
tion, structure, and presentation are conceptually
separated, MMBase provides modular and replace-
able implementations (i.e., printing, mobile, mail,
flash). MMBase is object-oriented. Content in
MMBase consists of objects, which are described in
XML (Extensible Markup Language) and Java and
are presented in an ‘‘object cloud.’’ This has the
advantage that content has to be stored only once.
However, to many smaller organizations this has the
disadvantage that every form of content must be
described as a component and needs to be stored
according to similar standards. This requires initial
investment of time and effort upon storing the
content. These costs can exceed the benefits,
especially in smaller organizations where the com-
plexities and heterogeneity of content are relatively
MMBase is licensed as an open-source software
project. The license with which MMBase is pro-
tected is the Mozilla** Public License (MPL). This
licensing scheme has several advantages. There is
no licensing fee that needs to be paid for MMBase.
This does not necessarily mean that MMBase is less
expensive than other CMSes, as this depends on the
total cost of ownership (TCO). However, it does
make MMBase attractive, as the licensing costs are
very clearly visible and quantifiable. In addition,
compared to the GPL (General Public License), the
MPL poses less risk to corporate users. One of the
important characteristics of the MPL, as compared
to the GPL, is that it is ‘‘non-viral’’ ; that is, software
integrated with the MPL does not need to be licensed
under the MPL upon distribution.
MMBase is compliant with the J2EE** (Java 2
Enterprise Edition) platform. Currently, the market
is dominated by two standards, namely .NET** and
Although, it is not clear in which direction
the market as a whole will move, it is clear that
these are currently the two most likely standards to
prevail in the future, and their dominance is most
likely to increase.
MMBase supports the concept of multichanneling.
Strict separation between content and layout and the
object-oriented structure facilitate the presentation
of content on various media channels. This charac-
teristic is partly due to the origin of MMBase in the
broadcasting industry. This industry has very
stringent requirements regarding the management
of content and its presentation.
MMBase does not
itself store or offer streaming-media facilities.
Streaming media are addressed by storing a refer-
ence to a resource on dedicated streaming servers.
The MMBase media project offers a way to include
information about the streams with these references,
such as bandwidth and type, allowing for filtering of
streams by user preference, and showing fragments
of a stored stream (e.g., ‘‘the first 6 minutes’’ ).
MMBase has proved to be very scalable. Some of the
organizations that have adopted MMBase manage
millions of objects in various formats, such as video,
audio, and plain-text documents. An example is
VPRO, which currently has eight million objects
MMBase is continuously evolving and gaining in
functionality. Partly due to the fact that the software
is open source, new functionality is constantly
added. Everyone in the community is welcome and
encouraged to contribute new add-ons to the
existing system. Newly added functionality includes
poll, chat, shop, and forum services. However, the
voluntary community-like structure also has its
drawbacks, such as ‘‘free-riding’’ (this issue will be
discussed more extensively later in this paper).
MMBase poses a steep learning curve for first-time
users. As mentioned previously, every item of
content has to be stored as an individual object,
which requires relatively high initial investment. In
addition, MMBase consists of many configuration
files whose relation can at times be unclear. First
time users have to learn many syntaxes and
functionalities, for instance ‘‘taglib’’ and edit wiz-
ards. A taglib, or tag library, is a set of actions that
encapsulate functionality. These tags are then used
within JSPs** (JavaServer Pages**). Finally, to
write queries in MMBase is not straightforward and
requires significant analysis. These are among the
reasons why first-time users might experience
difficulties when adopting MMBase and why they
need to make relatively high initial investments.
This paper addresses the growth of the MMBase
software and community. First, it addresses the
history of the software, relates the decisions and
happenings at the heart of the software, and briefly
introduces the structure of the MMBase community.
Next, it presents the architecture of MMBase. The
third section presents examples of organizations
that adopted MMBase and describes how software
vendors currently use the package to deliver value
and performance to customers. This section is
primarily based on interviews with stakeholders
who were involved in the adoption and implemen-
tation of MMBase. The fourth and final section
identifies and discusses three challenges facing the
MMBase community and the software itself.
The origin of MMBase can be traced back to VPRO.
VPRO is a Dutch public broadcasting corporation
with more than 320,000 member subscribers. The
corporation is well-known in the Netherlands for its
innovative programs and its focus on creativity.
In 1994, VPRO gathered a group of 20 people to
move the corporation from the analog into the
digital environment. The team created several
products including television programs about digital
issues, CD-ROMs, meetings, and lectures, and they
identified and developed many kinds of online
activities. Within weeks, VPRO was connected to
the Internet, and a Web site was created. The team
also set up a free public modem bank because at that
time Internet access was still relatively difficult for
many viewers. Via the modem bank, visitors could
look at the broadcasters’ Web site to check the
VPRO program schedule or details of their favorite
television shows.
VPRO’s primary goal regarding digital media was to
provide a learning environment for its content
creators, approximately 200 in total. They were
encouraged to explore the environment to find new
ways of expressing themselves and stimulating the
public. This resulted in numerous new and pio-
neering products, many of which were far removed
from the then stereotypical activities of broad-
casters. An example was the design of the VPRO
Web site itself, which appeared in a special online
gallery of the San Francisco Museum of Modern Art.
During this transition to digital content, the techni-
cal staff was challenged to provide and maintain an
infrastructure and toolset that would allow the
content creators to actualize their new concepts. In
1994, the market for Internet tools was still in its
infancy, and few tools of real value were available.
This situation forced VPRO to hire new staff (around
20) to create and maintain a whole range of new
tools; they included programmers, graphic design-
ers, and staff supporting the users of the new tools.
Most of the tools were created in 1994 and ranged
from games for children to new content for tele-
vision and radio. They relied primarily on the CERN
(Conseil Europe
´en pour la Recherche Nucle
server and the Common Gateway Interface (CGI), a
standard for interfacing external applications with
information servers, like Web servers.
However, the VPRO Web site team faced a difficult
capacity problem. All content on the site was based
&The MMBase Management
Committee worked hard to
create a community &
on CGI and was dynamically generated; by contin-
uously promoting the Web site on television, the site
was attracting many visitors, easily reaching
200,000 hits a day. At that time, the infrastructure
was simply not able to deal with this amount of
traffic, and the VPRO Web site faced serious
performance problems as a result. Something had to
be done to address this problem.
Collaboration with Sun Microsystems, Inc.
In late 1994, a solution presented itself when VPRO
was invited to join a testing program initiated by
Sun Microsystems, Inc. for a project called OAK.
OAK is the software language now better known as
Java. At the outset, Sun asked the VPRO team to
write client-side applets. Yet the VPRO team soon
realized there were strong arguments to redesign all
the server-side code in OAK because CGI simply did
not perform well in the UNIX environment. With
CGI, a fork had to be created each time a request
was made to an external program. The team realized
it would be better to ‘‘extend’’ the server and make
the functions part of the server itself. The solution
was to build an architecture based on ‘‘workers’’ and
modules, similar to the usage today of servlets and
persistent beans. These changes created a huge
boost in both performance and flexibility on the
server side for the VPRO projects.
At the time, another concern was the lack of Java
Web servers. VPRO decided to craft a new Web
server called Java HTTPD. By the time Java was
released to the general public, most VPRO-managed
Web sites were already running on server-side Java
The creation of MMBase software
In time, all of VPRO’s tools, servers, scripting
language, and database connectors were recoded in
Java and deployed on VPRO’s Java-based server
called James. Typically, the code became unman-
ageable as both the Web and the number of projects
grew. The team decided it was again necessary to re-
work all the code of each major project, an effort
that had, as we will explain, mixed results.
In 1996, during a large Dutch festival which VPRO
covered for radio, television, and the Internet, it
became clear that something in their Internet system
was faulty when the system ‘‘crashed.’’ For three
days the technical staff was unable to stabilize the
servers. VPRO had anticipated such problems when
using new technology in 1994, but not two years
later. The system had to be redesigned, and the
result was the creation of a new extension to James,
to be called MMBase. After months of research the
goals of the extension were defined:
Create a way to store all content of all projects in a
consistent manner;
Implement an extensible flexible structure to store
Create a tool for content creators to add, delete,
and change content;
Separate content from presentation;
Create a ‘‘metatag’’ schema (i.e., define a data
model wherein there is meta-data for each object
of any type);
Ensure that the system works across multiple
machines (i.e., clusters); and
Make sure no content (audio, video, or graphics)
is destroyed by making it ‘‘Web ready’’ —that is,
store all content in a high quality format.
Development of MMBase started in late 1996, and
the first version of the system was in use in 1997.
Back then, MMBase was a module in the James Web
server. As time progressed, more of the identified
goals were achieved, and gradually the outlines of
MMBase as a CMS became visible.
Opening the source code
Parallel to the development and improvement of
MMBase, the VPRO Web site began to gain acclaim
and attract visitors worldwide. These visitors also
discovered the MMBase development team. The
team was proud of its product and created demos,
which it showed to visitors. As a result, a growing
number of requests to use the software arrived.
Apart from being a publicly funded organization,
saying no to such requests went against the VPRO
corporate culture.
In 1999, VPRO took the first steps to make the
MMBase software open source. There were two
main motivators for this move: Firstly, VPRO had
become dependent on MMBase, but being the sole
creator, maintainer, and user of the software posed a
continuity risk. Opening up the source code would
enlarge the user base and attract others to partic-
ipate in development and maintenance. Secondly,
MMBase was created using public funds which,
VPRO reasoned, should in some way be returned to
the public. Making the code open source was one
way to return benefit to the public domain.
One developer was assigned the task of preparing
some 500,000 lines of source code for its first open-
source release. The primary challenge was to make
MMBase less VPRO-specific and more generic. A
secondary challenge was to ensure platform inde-
pendence. In addition, an open-source infrastructure
was required: a Web site, documentation, main-
tainers, and communication facilities such as mail-
ing lists were set up in just five weeks. And of course
a logo was created, which remains unchanged. The
focus of the Web site and (early) communication
was not on ‘‘selling a product,’’ but on ‘‘ spotlighting
the concept.’’
The developers who had worked on MMBase for
almost five years were very aware of the dilemma
they faced. Further improvements of the software
before the first open-source release would mean that
they would continue to be isolated for some time.
They also knew that they would never feel that
MMBase was finished. They therefore decided to
make the release quickly and accept the conse-
quences. They hoped that many other developers
would join them and want to contribute to the
collaborative effort.
The creation and rise of the MMBase community
The first open-source release of MMBase was on
April 3, 2000. The Web site that hosted the first
release is still home to the MMBase community.
The software was licensed under MPL.
To help
decide which license would be issued with MMBase
and what the community structure would be, the
team studied a number of open-source communities,
especially the Apache** community. The MPL
license was chosen because it allowed more freedom
and opportunity for entrepreneurial initiative com-
pared to the more popular GPL.
The rules and
regulations governing the MMBase community were
based on those for Apache; in fact, the Apache
community was approached directly for permission
to do so.
In line with the Apache community, the MMBase
Management Committee (MMC) was set up. The
first MMC consisted of four experienced project
leaders: two from VPRO, one from an independent
software vendor, and one from another public
broadcaster. A year later, a fifth member was added.
Membership in the MMC rotates annually. Each year
the two longest-serving members give up their
position, and two new members are chosen from
among the ‘‘committers.’’ To become a committer a
developer has to be nominated by the current
committers. The committers then vote to decide if a
candidate developer will be awarded committer
status. Once a developer has received committer
status, he or she can add source code directly to the
CVS (Concurrent Versions System).
The MMC worked hard to create a community and
spent much energy in coordination. However, it
soon realized that for the community to mature,
more was required than a robust technical product
and a developers’ community. By late 2001, a
number of organizations were discussing the desir-
ability of creating a foundation that could support
the roles of coordination, marketing, answering
questions, responding to requests for information
(RFIs), and establishing user collaboration and
knowledge exchange. The MMBase Foundation was
established in 2002.
The MMBase Foundation plays a key role in
promoting and informing the public about MMBase
and about open-source software and open standards
in general. A nonprofit institute, its main objective is
to facilitate the MMBase CMS for open-source usage
with the related community, focusing on stability
and innovation. Today the Foundation has grown to
include a few dozen (commercial) partners. It has a
CEO, a board, and an advisory committee of
partners, developers (the MMC), and users.
The Foundation’s primary focus is on the interests of
the users and commercial partners, as the devel-
opers have their own organizational structure, but it
supports the developers where and if necessary. The
Foundation’s main activities can be summarized as
Coordination—Bridging the gap that frequently
arises between developers and users. Further-
more, the foundation creates a long-term vision
for the software in close collaboration with the
developers’ community.
Moderation—Moderation between the supply of
MMBase software and the demand for it.
Knowledge transfer—Taking an active role in
disseminating knowledge, giving presentations
about MMBase, organizing events, and providing
Documentation—Active participation in the crea-
tion of documentation for the developers’ com-
munity, service providers, and users.
Marketing and promotion—Taking an active role
to ensure steady growth of the MMBase com-
Research and development—Stimulating and ini-
tiating research and development projects.
Collaborative development—Organizing regular
meetings with users and service providers to
stimulate collective development efforts and as-
signments. An example is the annual MMBase
This section discusses the basics of the MMBase
architecture. It touches upon five elements in the
architecture: object orientation, implementation
languages, database abstraction, application server,
and publication. The strength and presence of these
elements, making MMBase a flexible and well-
featured CMS solution, are a major reason for its
Object orientation
MMBase has made one concept central: namely, that
each content item within the system is viewed as an
object. This means that a person or program is
represented by an object, rather than by a document
describing them. In the world view of MMBase,
content is an object cloud. Behind this simple yet
powerful design is the idea that content stored today
may be required for other uses in the future, on
different channels, so it must be stored in an open
format with relationships to other stored content.
Publishing the content today (or in the future) is
only the next step, not the end goal of the process.
This sets MMBase apart from page-based and
document-based systems that take publishing as
their conceptual starting point.
All of the objects to be mapped into the MMBase
‘‘cloud’’ are defined in XML. The types of objects in
MMBase have an internal definition because no two
databases agree on a clear set of types. All objects in
MMBase can be related to each other. These
relations are also viewed and treated as objects
themselves. The most basic relation is one that
connects two objects but that does not contain any
content. However, frequently it is not enough to
make a relation between two objects. For instance,
when adding news items to a magazine, one also
needs a way of telling in which sequence the news
items should be placed in that magazine. In
MMBase, one can use the ‘‘posrel’’ relation for this
purpose. The ‘‘posrel’’ relation not only connects
two objects, but it also allows users to store an
integer value for this relation in the ‘‘pos’’ field of
the relation. In general, MMBase allows the creation
of relations with whatever fields are needed for any
particular content model. For instance, when con-
necting employees to departments, one can use a
relation that contains an extra string field to store
information on the functions that employees have in
their departments.
Originally, the designers and users of MMBase
required an architecture that allowed them to
change how content was used because standards are
constantly changing, as are user requirements and
ideas for using content. Though MMBase has
undergone many changes over the past eight years,
two fundamental precepts have endured. The first is
the base concept of storing content as objects with
relationships (the result being that even the oldest
installations can be kept compatible). The second
enduring precept is that parts of the proprietary
environment are replaced when clear standards
have emerged and been accepted.
Implementation languages
XML and Java were the first two standards that
became clear starting points for tooling during the
conception of MMBase. All objects in MMBase are
made up of a combination of both data and
functions, and the best tools available for imple-
mentation during MMBase’s development were
XML for data and Java for functions. Both are open,
platform-independent, well-defined standards with
broad support within both the commercial and
open-source community. Over time, both Java and
XML have continued to change; MMBase changes
with them when market forces indicate the time is
right, for example, the shift from Java Version 1.0.2
to Version 1.4. Taking these two technologies as a
base reduces the learning curve for many people to
join the MMBase community because XML and Java
have a large following and are well understood
within the developers’ community.
Database abstraction
MMBase stores and maintains the object cloud
through a storage manager, and queries the cloud
using a search query handler. These are two more or
less mutually independent abstraction frameworks,
and they are discussed in some detail later. The two
frameworks ensure that users are not confined to
one database, which would result in a vendor lock-
in. They also attract more people to use MMBase
because most companies have one database brand
for all of their systems; whereas, the open source
community uses a number of popular databases
such as MySQL and PostgreSQL.
There are many standards in the database world,
like Structured Query Language 92 (SQL92)
(Java Database Connectivity),
but almost
all larger databases break or extend these standards
as they see fit. To deal with this problem, MMBase
currently has its own object mapping mixed with
standards such as JDBC to get a completely trans-
parent storage model for its supported databases.
Furthermore, the MMBase clouds can be moved to
any supported database without any change in
content, software, or scripting, and new databases
can be supported if needed by adding new inter-
The storage-manager framework takes care of the
creation of tables, inserts, and updates. Objects are
mapped to the database depending on whether and
how that database supports object-oriented data
storage. In cases of non-object-oriented databases,
MMBase simulates this structure by duplicating data
in tables, specifically in the tables for the object
types from which other types inherit: ‘Object’ and
‘Insrel’. An alternate implementation is in develop-
ment. This implementation will make use of ‘views’.
Because the storage layer is pluggable, it is possible
to play on the strengths of the database, for instance,
by using the object-oriented features of a database
like Informix. Adapting the storage layer to support
a new database can be done through implementa-
tion of a new Storage Manager class, or through the
configuration of the existing base implementations,
that is, the Database Storage Manager and the
Relational Database Storage Manager. The existing
base implementations include a wide variety of
options, a set of query template strings which allow
&Each content item
within the system is viewed as
an object &
for variation in insert/update/create query syntaxes,
and the mapping of MMBase field types to actual
types in the tables.
Because support for the storage of binary data in
JDBC varies widely among databases (even among
versions of the same database), and because it often
introduces dependency from external (often license-
protected) source code, MMBase allows an option to
store binary data outside the database, on a file
system. This method may also be preferred for
practical reasons (such as a better facility for
backups). Local implementations are still possible,
to extend the layer to include binary data in the
database if there is no proper support in the JDBC
driver for that database.
The query-handler framework is used to retrieve
data from the database. It features query objects that
can be used to model a SQL ‘‘select’’ query. Those
objects can be handled and filled programmatically,
and only on execution of the statement are they
translated to actual SQL. Different databases may
have a slightly variant query handler to perform this
translation. The default implementations shipped
with MMBase support a common-denominator
version of SQL supported by all common databases.
The query objects are used as a key for query result
caching, substantially reducing database load.
The storage-manager framework is accessed only
from the core in MMBase. External programs never
deal with that layer directly, but instead pass their
requests for changes to MMBase through a ‘‘ bridge’’
called the MMBase Cloud Interface (MMCI). That
interface also allows the creation of query objects as
outlined earlier. MMBase has created its own
interface, which does not yet conform to the Java
Specification Request 170 (JSR 170) standard.
There are a few practical reasons why this is so.
First, the MMCI was created before the JSR 170
existed. Second, the standard has been received
with significant criticism. Third, changing the MMCI
would require much effort, due to the changes that
need to be made to other products that use the
MMCI, of which the MMBase tag library is a good
Like most CMS systems, when used to support Web
sites, MMBase is paired with a (Java-enabled) Web
server or an application server. See Figure 1 for an
overview of a Web server infrastructure with
MMBase. Originally, VPRO started with James, a
Web server created by the VPRO team. After the
servlet API (application programming interface)
gained acceptance, MMBase was adapted to support
the various versions of that API. Currently, the
servlet API is only a small part of the J2EE
specifications, a set that is not always clear because
it covers a large area and is subject to constant
change. However, J2EE is a good partner for
MMBase because it demands a lot of the server
resources that MMBase is running on.
MMBase is a J2EE application. As more of the J2EE
specifications become stable and accepted, custom
layers will be swapped out of MMBase and handled
by the J2EE server. A good example is database
abstraction. Currently, J2EE is not strong enough to
cover the database abstraction now available in
MMBase, but with successive iterations of the
specification, the gap is shrinking. At some point,
MMBase database abstraction may be replaced by
abstractions provided by the J2EE server of choice.
MMBase is used as a Web application on an
application server. Content is stored and maintained
via import components, like the edit wizards or the
XML importer. Different components can be used to
extract content from the MMBase content reposi-
tory. Both internal and external caching mecha-
nisms are available to boost performance.
Fundamental for a CMS is the manner in which
content is translated to the required published form.
MMBase is often used to create Web sites. Unless
the site in question has a very fixed user-interface
design, tools are required to help the site developers
create the necessary Web pages (or documents,
streams, etc.). The number of frameworks available
on the Internet, both large and small, is almost
limitless; the same applies for the number of in-
house created tools. MMBase started out with its
own scripting language. As with most of these
language types, its support is paramount. Most Web
developers are trained in one or two of the main
scripting systems, for example Active Server Pages**
(ASP), Personal Home Pages (PHP), or JSP, so it is
most efficient to make use of this familiarity. To
enable broad support, a special layer between the
MMBase core engine and the outside world was
added, namely, the MMCI.
Over the years, a taglib has been created for MMBase
for use in combination with other taglib sets or
independently, to create dynamic Web pages filled
with content stored in MMBase back-end servers.
Many example packages are provided in the distri-
bution set, which serves as a starting point for new
developers of MMBase-driven Web sites. See Figure 2
for the role of the MMCI, the taglib, and packages in
the MMBase architecture. (Dove, one of the compo-
nents shown in the figure, is a support class that
Figure 1
Overview of MMBase Web server infrastructure
Operating System
JavaServer Pages
XML Interface
Image Converter
Input of Text,
Images, Sounds
and Movies
on Web Site
Application Server
supplies a communication protocol for MMBase.)
Over time, the core developers will adapt the scripting
tools when new standard solutions to problems
become available (currently the effects of JSP2 and
how to convert to it are being hotly debated).
As shown in Figure 2, the MMBase architecture
consists of five layers: (1) the Database Access layer,
which connects MMBase to a database via the JDBC
interface, (2) the MMBase Core, which maps the
relational database into an object-oriented abstrac-
tion layer, (3) the Security layer, which provides a
pluggable security interface for user authorization
and authentication, (4) the MMCI, which facilitates
communication between the Core and Security layer
and the components, and (5) the components,
which provide the basic building blocks to import
into, edit, and extract from the MMBase object
repository. Packages are MMBase (Web) applica-
tions, which use the components and offer a ready-
to-use item of functionality like a forum, chat, or
e-learning platform.
As the MMBase software matured, a growing
number of users, many from the public domain,
began to employ it. One of the first users of MMBase
was the Dutch Evangelical Broadcasting Organiza-
tion (EO). It adopted MMBase for a number of
reasons: (1) MMBase is open, allowing the organi-
zation to make its own modifications to the
software; (2) MMBase is based on Java and XML,
thus it is standards-based and platform-indepen-
dent; (3) MMBase is designed to be flexible; and (4)
MMBase was already successfully used to support
VPRO’s Web site, which meant that it would also
likely fulfill EO’s requirements.
After the EO, many more organizations began to
adopt MMBase. A selection of these organizations
follows. These case studies will primarily focus on
the reasons that led to the adoption of MMBase and
on the lessons that were learned.
Ilse Media
In the late nineties, Ilse was the leading search
engine for the Dutch-language region. In 2000, Ilse
merged with the magazine division of VNU Pub-
lishers, which is now part of Sanoma. The core
competence of Ilse Media lay in search engine
technology; the organization had much less
knowledge of Web site technology. This posed a
challenge because Ilse Media was now being asked
to host the Web sites for all VNU-published
Figure 2
MMBase architecture
Dove Edit Wizards
MMCI (Bridge)
Cloud Context Basic
MMBase Core
Builder Node Transactions Multicast
Database Access
Query Storage Support
MMBase interface
Core components
magazines in an efficient and cost-effective way. In
the first months of 2001, Ilse Media conducted a
CMS selection process. The programs under review
included Mediasurface**, Roxen, Gauss, Tridion**,
Zope**, and MMBase. MMBase was selected be-
cause it offered the latest technology, such as JSP
templating, object orientation, platform independ-
ence, and XML import and export; it had a robust
and growing installed base in the Netherlands; it
was open source, so that an MMBase implementa-
tion could easily be exported to another CMS; and it
came without licensing fees.
Within a few months, a group of three developers,
one designer, and a project manager was able to
build a dozen Web sites for VNU magazines.
MMBase proved efficient in implementing tailor-
made solutions generated from a generic blueprint.
The main reason for this is MMBase’s object-
oriented architecture, which eases the implementa-
tion of generic building blocks. At the same time,
MMBase offered the flexibility to diverge from and
add to the blueprint where necessary.
In 2002, an important Dutch online news provider,, also decided to adopt MMBase. This project
resulted in a valuable spin-off called Wodan.
Wodan is a reverse proxy module for the Apache
Web browser. Web clients retrieve content from the
Wodan module instead of from the Web server. The
module is especially useful in environments where a
large amount of CPU power is required, but where
the pages do not change often.
The city of Amsterdam
In 2000, Amsterdam faced an organizational prob-
lem. The city had an enormous number of Web
sites, which were created and maintained by
numerous people. The infrastructure had become a
convoluted structure in which everything was
connected in multiple ways. Each city district and
department and their related agencies had their own
Web sites based on their own preferences. Further-
more, the city knew from experience that top-down
control to change this structure was unlikely to have
positive effects. Traditionally, the departments are
accustomed to a great deal of autonomy, which they
value highly.
Amsterdam was fortunate to have an IT-conscious
councillor for economic affairs and a capable senior
project manager at its central information facility.
Together, they decided to transform the city’s IT
infrastructure and to make the move to open source.
The main reasons were that open source would
allow the city to maintain independence from a
supplier and would enable the city to share any
written source code with the public. The adoption of
open source was also considered a signal to the
outside world, as it would enhance the openness of
the municipality. The choice to move to MMBase
was based on two factors. First, content in MMBase
is stored in XML. This would enable the city to
switch to another CMS if MMBase proved to be
qualitatively inadequate. Second, the origin of the
system in the broadcasting industry seemed perfect
considering that city council meetings were to be
broadcast on the Web in the future. One of those
directly involved in the decision commented, ‘‘It
seemed flexible and future minded, and for the rest,
it was intuition.’’
For municipal use, the application Web in a Box
(WIAB) was created, an MMBase-based environment
with advanced editing facilities. The first version of
WIAB was released in February 2002 and licensed
with GPL. This decision resulted in some contro-
versy. Although MPL and GPL are both open source
licenses, they are not compatible. A special clause in
GPL forbids developers from incorporating GPL-
licensed source code into software licensed under
It took a year before the WIAB license was
changed to MPL, which enables the WIAB project and
the MMBase community to benefit from each other’s
activities and improvements. It also ensures that
WIAB can remain compatible with the MMBase core.
In late 2003, a large shared development fund was
established and contributions were provided by
every agency using WIAB. In return, they received a
strong say in the identification and definition of new
requirements for future versions of WIAB. The
system is gradually growing into a real network of
interconnected databases, and the benefits of
interoperability and the opportunities for knowledge
exchange and Web service engineering are gradually
becoming visible within the city as a whole.
Currently, more than 28 independent agencies use
the same components for Internet services, and
seven agencies manage their whole intranet based
on WIAB. The benefits of a developer community
consisting of a large city’s administration and end
users and characterized by high coherence and
common understanding of Web technologies are
already visible. The first advantage which is not
obvious is the speed of useful metatagging among
civil servants and the fact that one search engine is
available to all agencies without any technical
indexing problems. The organically grown balance
between centralized databases and distributed da-
tabases using multiple retrieval mechanisms is
something any systems architect would like to
accomplish in such a complex political climate.
Integration and compatibility with GIS (geographic
information systems) appears to be easier than
The initiators also expressed some of the disadvan-
tages. They felt that adoption had necessitated
complex organizational change and the creation of a
culture of interdepartmental collaboration beyond
that which the IT managers were accustomed to
handling. They also mentioned some of the diffi-
culties in setting up the maintenance organization.
This differed from the situation in which a ‘‘simple’’
vendor would have been chosen. Finally, in hind-
sight, it would have been valuable to have known
more about license issues and the fact that one type
can exclude another.
The Vodafone Group commissioned research, de-
velopment, and implementation of a software
application for conferences and events aimed to
support business and public events, providing extra
information and assistance to attendees via mobile
telephone. The content for such a system needs to
be extremely dynamic, and the ability to straight-
forwardly make relationships between content items
is crucial. MMBase proved ideal for these require-
ments. Among the major reasons for Vodafone’s
move to MMBase were the following:
No commercial license costs
Proven stability and performance
Availability of support from MMBase developers’
and software vendor communities
Low development and maintenance costs, com-
pared to other CMSes
Another motivation for Vodafone was the ability to
combine MMBase with the open-source Xmedia
portal, implemented at various other sites. The
Xmedia portal allows MMBase-controlled content to
be made available over multiple channels, such as
mobile telephone and digital television, and also
provides enhanced security and a service-oriented
Vodafone is converting more of its public systems to
MMBase and is currently engaged in a set of pilot
&The open-source
development model is based
on the principle that
knowledge is free and
should be shared &
projects to examine the associated technical and
business issues.
The Mediator Group is an innovator in the field of
education and specializes in e-learning technology.
Mediator serves organizations that want to use IT to
support their primary education process. The
Mediator Group wanted to create a simple Web-
based e-learning platform that would free organiza-
tions to spend their innovation budgets on truly
educational innovation. It faced a challenge in
deciding which development platform to choose. It
soon recognized open source as a promising route,
as this would reduce commercial licensing costs for
clients. Mediator approached a number of organi-
zations and asked them to write proposals for a new
platform. They defined three criteria: (1) the plat-
form should be open source, (2) it should be based
on the learning objects methodology, and (3) it
should meet open and didactic standards.
In the meantime, a client asked The Mediator Group
to collaborate on and provide support for an
MMBase implementation. Mediator became in-
volved in the MMBase community and soon realized
that MMBase was suitable to create their generic
e-learning platform. Their main reasons for selecting
MMBase were that it had been developed by media-
rich organizations and that it had a solid user and
developer base. The Evangelical Broadcasting Or-
ganization joined the development effort, as it too
was interested in creating an e-learning platform.
Their combined effort resulted in creation of the
open-source platform Didactor.
Within as well as outside of the MMbase commun-
ity, several parties showed interest in Didactor
initially. However, very few actually supported
Didactor by co-developing or funding. This resulted
in the odd situation where the founding partners
made large investments in terms of time and budget;
whereas, others simply waited for Didactor to be
finished. This is one of the less positive character-
istics of open-source software, as it supports and
perhaps even stimulates ‘‘free-riding.’’ Software
development depends on companies and individuals
who are willing to do the job.
The platform is developed from a didactic perspec-
tive, which is considered to be one of the most
crucial prerequisites for successful implementation
of e-learning.
Furthermore, it is based on the
methodology of learning objects, which is an
important trend in e-learning.
The idea underlying
this methodology is that educators can define and
create pieces of knowledge and then group them
into separate objects. These objects are stored in a
database and described with educational meta-data.
This structure allows educators to share objects and
combine them to create lessons or courses.
The Didactor architecture meets international
standards like the IEEE Learning Object Metadata
(LOM) standard
and the Sharable Content Object
Reference Model (SCORM).
Developers are now in
the process of integrating the flexible generic
language IMS (Instructional Management System)
Learning Design.
The Dutch Open University
collaborates with The Mediator Group in this
process. Didactor consists of over 20 didactic
components, which remain close to the components
in MMBase; that is, they use the same forum and
chat components. New modules created in Didactor
are programmed in the same way as the components
in MMBase. New modules are donated to the
Didactor is used by institutes for vocational training,
as well as by companies seeking to redefine their
learning methods. ConQuaestor, which used to be
part of IBM Business Consulting Services, has also
adopted Didactor. The Mediator Group and NETg,
which is part of the Thomson Corporation, formed a
strategic partnership to deliver NETg’s roughly
3,000 e-learning courses through Didactor. The Free
University, one of the leading universities in the
Netherlands, is involved as a research partner in this
project, measuring the efficiency of the platform in a
learning environment.
One of the lessons learned by Mediator, starting
with the development of its components, was that it
was not easy to begin using MMBase. The most
important reason for this was probably the fact that
one cannot simply contact the MMBase vendor.
There is no single point of contact. Corporate users
can only rely on one of the supporting partners, but
this can become problematic when their customers
demand tight time schedules. The open-source
communities, which consist of many volunteers
who participate for various reasons, including fun
and ideology, are less concerned with deadlines
than the corporate users.
For Mediator, the
solution for this issue was to become involved in the
community and to build relationships with members
based on trust. This way others will be more
inclined to help Mediator when certain problems are
experienced or deadlines have to be met.
Because Didactor is mission-critical for organiza-
tions, service delivery has become increasingly
important. The main parties supporting the product
are thus in the process of creating a shared service
center. In the shared service center, trained profes-
sionals will manage the Didactor service agreements
and be responsible for Web site hosting, fixing bugs,
making updates available, and providing continuous
service (i.e., ‘‘24/7’’ ). For the Mediator Group, this is
one of the most important issues affecting any open-
source product: the variety and quality of services
has to be the equal to or even better than that of
proprietary products in order to be able to compete
with them.
Three distinct challenges have arisen from the
growth of the MMBase community. The first is how
to deal with the potentially growing number of free
riders. The second is to define and separate the core
from the packages (previously called MMBase
applications). The third challenge is documentation.
These challenges are described in the following
Free riders, the other side of openness
The open-source development model is based on the
principle that knowledge is free and should be
shared. Richard Stallman compares the art of writing
software with that of writing a symphony. He argues
that Beethoven could not have written music with-
out building on the ideas of other composers, and
the same is true for software developers. They also
build on the ideas of other developers, and there-
fore, he argues, it is important for them to share and
have access to software source code.
However, having source code freely available also
creates problems. Anyone can download, install,
and modify source code. Some open-source licenses
even allow users to create a proprietary, that is,
closed, version of the software. These factors result
in the potential for organizations to ‘‘free ride’’ : they
can take without giving.
Free-riding behavior is not unusual. It occurs in
many open-source communities, and the MMBase
community is not immune. It is not inherently
problematic if a small number of users decide to free
ride. However, a community like MMBase needs to
retain a critical mass of users and software-devel-
oping companies who are willing to participate in
the maintenance and improvement of the software.
The question is, ‘‘How?’’ To understand the value of
such involvement for developers and maintainers
and how such communities can protect themselves,
it is important to understand how participants are
attracted to the community in the first place.
Basically, there are two types of participants: the
commercial vendors that build their business model
on the open-source application (in this case,
MMBase) and the users.
In the past, one would not have expected a
commercial vendor to become a partner in an open-
source community. Freely sharing and contributing
improvements made at their own expense would
seem counter to commercial principles. Tradition-
ally, vendors have had an incentive to keep
modified source code private, as this is a recognized
way to build and protect a competitive advantage in
the software market. However, to date, most
commercial vendors of MMBase-related material
have become partners in the community; most
vendors want to join the community. Several factors
help to explain why:
1. The community’s mediator role in the user
market—Firstly, the MMBase community is well
known in the Netherlands and enjoys a good
reputation. For this reason, many potential users
first approach the community rather than a
commercial vendor to find out more about the
software. The community brings these users—
potential clients—into contact with vendors that
can customize the software to meet the users’
needs. Thus, vendors have an incentive to
collaborate within the community, as it is an
important channel through which to reach
potential customers.
2. The community as source of continuity—Sec-
ondly, some users (including major industry and
government concerns) have made a strategic
decision to use open-source software. They do so
because (for example) they want to reduce
licensing costs and dependency on commercial
vendors. Such users often require commercial
vendors to return any additions or modifications
they contract to the community to ensure con-
3. The community as learning environment for
users—The motivation for users to participate
varies. Many smaller companies want a proven
solution at minimum cost and might hire a
commercial vendor to customize the software or
decide to install the software themselves, using it
as a finished product. However, for these users
there is also an incentive to be involved in the
community. Lack of proactive participation in the
community could lead to a lack of attention from
the developers and maintainers the next time an
update is required or when they need information
or experience a problem.
Thus, a community like that of MMBase has
informal mechanisms to overcome the problem of
free riding. These are not yet predictable processes,
however, and time will tell whether they are solid
enough to continue to motivate vendors and users to
collaborate and invest in the community.
Managing flexibility: the core versus the
During the conception of MMBase, things were
simple. There was one version of MMBase and one
community of developers. These developers knew
everything there was to know about the product.
They were the core developers. New developments
were added directly to MMBase, which slowly
evolved into a monolithic piece of software. This
process remained manageable due to the relatively
small size of the community.
However, as time progressed, increasing numbers of
organizations began to use the product and became
involved in its development and maintenance. New
functionality was added. Application developers
created new packages for use on top of MMBase.
This sometimes meant that changes to MMBase
were required, and these were integrated into
privately owned versions of MMBase. Frequently,
these changes were not integrated into the official
MMBase releases. Therefore, every time an official
release was made, an exponential time-consuming
migration effort was required to maintain the
The growing number of developers caused a steady
rise in the number of packages available for
MMBase, which extended the software’s function-
ality. Packages included new editors, a media
package enabling a comprehensive and generic way
to handle audio and video files, and an e-mail
package allowing users to send e-mail directly from
the CMS. Many of these packages were added to the
official MMBase release, causing the official release
to grow to an almost unmanageable size. A growing
number of packages and relationships had to be
managed and stabilized before each new release. As
a result, it became increasingly difficult and time-
consuming to create new releases.
The community of developers realized that a clear
separation was required between the core of
MMBase and the packages built on top of this core
(i.e., a more service-oriented architecture was
needed). The separation was initiated in 2003 and
currently dominates development activities. The
separation has as its main goal the creation of a
smaller, more maintainable core; creating an archi-
tecture that requires fewer changes at the core,
resulting in a more stable core; increasing the
number of official releases of MMBase packages
while shortening the release cycles; increasing
compatibility between releases; increasing coordi-
nation among active developers as a result of more
manageable components; attracting more develop-
ers and teams to participate, as the effort required
for effective participation is decreased; and defining
solid interfaces between the core and the packages,
ensuring that application developers can efficiently
create new packages and improve existing ones.
The road to a complete separation between the core
and packages is not without problems, however.
There are three major problems: The first is
distinguishing the core from the packages; that is,
how to decide what belongs to the core of MMBase
and what should be part of a package. The
underlying problem is the lack of consensus among
developers about what MMBase exactly is. The
developers can be roughly divided into four camps.
The first camp argues that MMBase is an object
database; the second considers it to be a frame-
work; the third views MMBase as a CMS; and the
fourth sees it as a combination of the three. These
different conceptions result in varying opinions
about what belongs in the core and what does not.
For example, if MMBase is viewed as an object
database, much of the source code can be removed
from the core, but from the CMS perspective,
features like workflow and security would have to
be included in the core.
The second problem is that of distribution and
packaging. The challenge is to create a framework
and format for how packages are to be created,
distributed, and installed. The third problem relates
to legacy code and backward compatibility. Part of
the code currently in the MMBase core is legacy
code. Only a limited number of organizations, those
that have used MMBase since the beginning, still
require this code. An example is the scripting
language SCAN that is used to create templates.
SCAN was replaced by the MMBase taglib (a
standard technique to create templates). Yet, as
some organizations still use the SCAN templates,
this code needs to remain available for them.
The community is well aware of the challenges
posed by separation of the MMBase core code from
its packages and is working hard to solve the
problems to achieve a healthy separation between
the two. To this end two projects have been created,
the first of which is cleaning. The goal of this project
is ‘‘refactoring’’ (removing or rewriting old code).
Some code will be moved into packages, redundant
code will be completely removed, and some code
will be rewritten for improved stability, perfor-
mance, and maintainability. Already, much code
has been ‘‘tagged’’ during the last two years.
Tagging involves adding keywords to parts of code
to describe future actions required (e.g., ‘‘rewrite,’’
‘‘add better documentation,’’ and ‘‘ remove’’ ). These
actions can be complex; hence the two-phase
process of tagging and then implementation.
The second project is called packaging. Its aim is to
simplify the installation process and management of
the packages. The result will be a small core that has
basic functionality. Users would then add function-
ality by installing the packages, supported by a
simple and uniform installation procedure.
Managing reusability: Writing and maintaining
As the MMBase software matures and becomes
more complex and extensive, the importance of
documentation increases. Lerner and Tirole identi-
fied the creation of documentation as a key
challenge facing many open-source communities:
‘‘Another challenge has been the apparently lesser
emphasis on documentation... in at least some
open-source projects.’’
This aptly describes the
challenge facing the MMBase community with
regard to documentation. Many developers prefer to
write new source code and create new functionality
and are not intrinsically motivated to write doc-
umentation. Users involved in the community
seldom have the expertise to write the appropriate
level of technical documentation. Moreover, they
may have insufficient knowledge of the software
and its functionality to do so. Nor do the commercial
vendors spending time and money to create new
MMBase software always have the long-term vision
or incentive to invest in writing documentation for
the software they create.
It was only in July 2002 that the MMBase
community was able to motivate its participants
sufficiently to invest in the creation of documenta-
tion. The community initiated the documentation
project to write and maintain the documentation
needed for future MMBase releases. At the start of
the project, the XML Docbook
was chosen as the
standard for writing documentation.
The community has since created and institutional-
ized two mechanisms to encourage developers to
participate in the documentation project and moti-
vate them to write new documentation. The first is
the organization of regular face-to-face meetings.
Participating developers have found that regular
meetings have helped motivate them to create and
improve documents. Peer pressure has thus proven
a successful way to compensate for any original lack
of incentive. At the meetings, developers review
existing documents and discuss future directions.
The second incentive is the community’s new policy
regarding releases: new releases are allowed only
when the documentation is up to date. Again, the
idea is to stimulate developers to participate in the
documentation project. As of this writing, the new
policy is undergoing initial trials, so whether it will
indeed stimulate developers to participate is as yet
By now, a dozen documents have been written. The
documentation currently available provides suffi-
cient information for new potential contributors and
users to find their way around the MMBase
environment. However, there are still blank spots
and a number of ‘‘to dos.’’ The future will tell
whether the documentation project and the two
incentive mechanisms are sufficient to mobilize a
critical mass of participants to keep the body of
MMBase documentation up to date.
This paper has discussed how the MMBase CMS was
created and how its community took form. It argued
that the strength of MMBase is that it is stable,
proven, platform-independent, object-oriented, and
open source. The continuous growth of the MMBase
open-source community and the rising number of its
users provides empirical proof of the value of the
characteristics mentioned. Furthermore, these two
trends highlight the need for and importance of an
organizational structure that is able to constantly
adapt and evolve to changing requirements and
demands. To date, the MMBase community appears
to have succeeded in meeting these requirements.
The authors would like to thank the members of the
MMBase Management Committee, and in particular
Rob Vermeulen and Pierre van Rooden, for their
contributions and comments. We would like to thank
Jeroen Visser (of IBM Netherlands) for his support
and his comments. Finally, many thanks go to Bert
Straatman, Michiel Meeuwissen and Rogier Schaaf
for their input and Karien Stroucken for her support
and coordination of the many activities needed to get
this paper published.
*Trademark or registered trademark of International Business
Machines Corporation.
**Trademark or registered trademark of Sun Microsystems,
Inc., Microsoft Corporation, Oracle Corporation, Linus Tor-
valds, Netscape Communications Corporation, MySQL AB,
PostgreSQL, Inc., The Open Group, The Mozilla Organization,
The Apache Software Foundation, Mediasurface Plc, Tridion
B. V., or Zope Corporation.
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8. MMBase Homepage, (July
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Commons: Self-Organizing Open Source Communities and
Innovative Intellectual Property Regimes, T. M. C. Asser
Press, The Hague (2003).
17. T. Govindasamy, ‘‘Successful Implementation of
E-learning Pedagogical Considerations,’’ Internet and
Higher Education 4, 287–299 (2002).
18. L. Mortimer, ‘‘(Learning) Objects of Desire: Promise and
Practicality’’ (2002),
19. Learning Object Metadata, Learning Technology Stan-
dards Committee, Working Group 12, http:// (July 2004).
20. Shareable Content Object Reference Model (SCORM)
Initiative, (July
21. The manual can be downloaded from http:// (July
22. See for instance: R. van Wendel de Joode, ‘‘Conflicts in
Open Source Communities,’’ Electronic Markets 14, No. 2,
104–113 (2004).
23. R. M. Stallman, Free Software, Free Society: Selected
Essays of Richard M. Stallman, GNU Press, Boston, MA
24. J. Lerner and J. Tirole, ‘‘Some Simple Economics of Open
Source,’’ Journal of Industrial Economics 50, No. 2, 197–
234 (2002).
25. The Docbook XML software (Version 4.2) and the project
can be found at
xml/ (July 2004).
Accepted for publication October 21, 2004.
Joost Becking
The Mediator Group, P.O. Box 59295, 1040 KG Amsterdam,
The Netherlands ( Mr. Becking is
co-founder and principal educational architect of the open-
source e-learning platform Didactor, and is responsible for
open-source strategy. He specifically focuses on expanding the
worldwide developer and user community. Mr. Becking co-
authored the book Internet Method on integrating Web
applications in primary business processes. His interests are in
the areas of open-source business modeling, standardization,
and learning object technology. He strongly believes that IT
can do a great deal of good in educational settings, but only if
it becomes part of the educational strategy for primary
processes, and so he strongly believes in the power of blended
Steve Course
Quantiq Xmedia B.V., 11–13 Koninginneweg, 1217 KP
Hilversum, The Netherlands ( Mr.
Course is CTO and co-founder of Quantiq Xmedia. Quantiq
brings IT and marketing and communication specialists
together to create value for clients, helping them become
cross-media driven by developing concepts and technical
implementations. Previously, he was the technical manager at
Vodafone, where he was responsible for the implementation
of the Vodafone Live! platform and the Vizzavi portal.
Gerard van Enk
Million Pieces, Kiekstraat 167, 1087 GT Amsterdam, The
Netherlands ( Mr. van Euk is a member
of the MMBase Management Committee and MMBase release
manager. His company, Million Pieces, specializes in Internet-
related development and consultancy. He is the senior Web
application developer for the Evangelical Broadcasting
Organization, a Dutch public broadcaster. His interests
include Java, open source (software, communities, licenses,
etc.), and free culture.
Published online April 20, 2005.
Hendrik Theodoor Hangyi
MMatch/MMBase Consultancy and Implementation,
Hommelstraat 9A, 3061 VA, Rotterdam, The Netherlands
( Mr. Hangyi is the project manager of the
MMBase documentation project. He has worked with MMBase
since 2001, focusing mainly on consultancy, implementation,
and education. Before starting his own firm, he worked as a
consultant at CMG and Arthur Andersen.
Jo Lahaye
MMBase Foundation, Neuweg 83, 1214 GM Hilversum, The
Netherlands, ( Mr. Lahaye is the first CEO of
The MMBase Foundation. He has a background in journalism,
worked as an ICT (information and communication
technology) project manager, and implemented many
different CMSes, especially in higher education. He also
advises many organizations on the use of open-source
software and is the author of many (Dutch) articles on open-
source and open-standards issues as well as (software)
Daniel Ockeloen crossmedia production company,
Rapenburgerstraat 109, 1011VL Amsterdam
( Mr. Ockeloen is a software designer.
With Rico Jansen, he was responsible for the development of
James and MMBase for VPRO. In 1999 and 2000, he prepared
MMBase for open-source release. In 2000, he left VPRO to co-
found the company Submarine, which produces cross-media
products. Mr. Ockeloen was part of the MMBase Management
Committee for the first few years of the open-source phase.
Currently, he works for Submarine and several other
supporting organizations to create new extensions for
MMBase. He plays a positive role in the community by giving
talks and lectures when time allows. He spends much of his
free time with music and movies in his self-built home theater.
Rob Peters
University of Amsterdam/Faculty of Law, Leibniz Center for
Law, Oude Manhuispoort 4, PO Box 1030, 1000BA
Amsterdam, The Netherlands ( Mr. Peters
organized the first conference on electronic commerce in
Europe in 1993. He was responsible for building some of the
Netherlands’ major government sites, like and He is now
in charge of a number of European research projects, such as Currently, he works for a small
consultancy firm for e-government called Zenc, specializing in
the link between content production and content navigation.
At the University of Amsterdam, he is completing a Ph.D.
degree on open source as a catalyst for e-government
Hessel Rosbergen
Finalist IT Group, 3 Wibautstraat 9th floor, 1091CH
Amsterdam, The Netherlands
( Mr. Rosbergen is account
manager at Finalist IT Group. Finalist specializes in technical
consulting and development services for the Internet, based
on Java technology. Most of the projects are based on open-
source technology, such as MMBase and JBOSS. Because
Finalist also uses SUN, HP, BEA, IBM and X-Hive, different
technologies can be thoroughly compared.
Ruben van Wendel de Joode
Delft, University of Technology, Faculty of Technology, Policy
and Management, P.O. Box 5015, 2600 GA Delft, The
Netherlands ( Mr. van Wendel de
Joode is a Ph.D. degree student. His research focuses on the
organization of popular open-source communities like Apache
and Linux. He received two grants from the Netherlands
Organization for Scientific Research (NWO) for research
related to open-source communities. The first grant was to
study the interplay between intellectual property rights and
open-source communities. The results are published in
Governing the Virtual Commons (Cambridge University Press,
2003). He has written numerous articles on open source,
which have appeared in journals like Electronic Markets,
Knowledge, Technology and Policy, and the International
Journal of IT Standards & Standardisation Research. &
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