Lada A. Adamic's research while affiliated with Meta and other places

Publications (129)

Preprint
Full-text available
We use de-identified data from Facebook Groups to study and provide a descriptive analysis of local gift-giving communities, in particular buy nothing (BN) groups. These communities allow people to give items they no longer need, reduce waste, and connect to local community. Millions of people have joined BN groups on Facebook, with an increasing p...
Preprint
We use exploratory factor analysis to investigate the online persistence of known community-level patterns of social capital variance in the U.S. context. Our analysis focuses on Facebook groups, specifically those that tend to connect users in the same local area. We investigate the relationship between established, localized measures of social ca...
Article
People assume different and important roles within social networks. Some roles have received extensive study: that of influencers who are well-connected, and that of brokers who bridge unconnected parts of the network. However, very little work has explored another potentially important role, that of creating opportunities for people to interact an...
Article
"Witkeys" are websites in China that form a rapidly growing web-based knowledge market. A user who posts a task also offers a small fee, and many other users submit their answers to compete. The Witkey sites fall in-between aspects of the now-defunct Google Answers (vetted experts answer questions for a fee) and Yahoo Answers (anyone can answer or...
Article
As online social networks expand their role beyond maintaining existing relationships, they may look to more faceted ratings to support the formation of new connections between their users. Our study focuses on one community employing faceted ratings, CouchSurfing.org, and combines data analysis of ratings, a large-scale survey, and in-depth interv...
Article
Online social networking tools are used around the world by people to ask questions of their friends, because friends provide direct, reliable, contextualized, and interactive responses. However, although the tools used in different cultures for question asking are often very similar, the way they are used can be very different, reflecting unique i...
Preprint
Full-text available
People assume different and important roles within social networks. Some roles have received extensive study: that of influencers who are well-connected, and that of brokers who bridge unconnected parts of the network. However, very little work has explored another potentially important role, that of creating opportunities for people to interact an...
Preprint
In the U.S., a significant portion of many people's life-long social networks is formed in college. Yet our understanding of many aspects of this formation process, such as the role of time variation, heterogeneity between educational contexts, and the persistence of ties formed during college, is incomplete. In order to help fill some of these gap...
Preprint
Anecdotally, social connections made in university have life-long impact. Yet knowledge of social networks formed in college remains episodic, due in large part to the difficulty and expense involved in collecting a suitable dataset for comprehensive analysis. To advance and systematize insight into college social networks, we describe a dataset of...
Article
Anecdotally, social connections made in university have life-long impact. Yet knowledge of social networks formed in college remains episodic, due in large part to the difficulty and expense involved in collecting a suitable dataset for comprehensive analysis. To advance and systematize insight into college social networks, we describe a dataset of...
Chapter
Social ties form the bedrock of the global economy and international political order. Understanding the nature of these ties is thus a focus of social science research in fields including economics, sociology, political science, geography, and demography. Yet prior empirical studies have been constrained by a lack of granular data on the interconne...
Article
Full-text available
Abstract In the classic “influence-maximization” (IM) problem, people influence one another to adopt a product and the goal is to identify people to “seed” with the product so as to maximize long-term adoption. Many influence-maximization models suggest that, if the number of people who can be seeded is unconstrained, then it is optimal to seed eve...
Chapter
Product-adoption scenarios are often theoretically modeled as “influence-maximization” (IM) problems, where people influence one another to adopt and the goal is to find a limited set of people to “seed” so as to maximize long-term adoption. In many IM models, if there is no budgetary limit on seeding, the optimal approach involves seeding everybod...
Article
Large cascades can develop in online social networks as people share information with one another. Though simple reshare cascades have been studied extensively, the full range of cascading behaviors on social media is much more diverse. Here we study how diffusion protocols, or the social exchanges that enable information transmission, affect casca...
Preprint
Large cascades can develop in online social networks as people share information with one another. Though simple reshare cascades have been studied extensively, the full range of cascading behaviors on social media is much more diverse. Here we study how diffusion protocols, or the social exchanges that enable information transmission, affect casca...
Article
In traditional models for word-of-mouth recommendations and viral marketing, the objective function has generally been based on reaching as many people as possible. However, a number of studies have shown that the indiscriminate spread of a product by word-of-mouth can result in overexposure, reaching people who evaluate it negatively. This can lea...
Conference Paper
Detecting large reshare cascades is an important problem in online social networks. There are a variety of attempts to model this problem, from using time series analysis methods to stochastic processes. Most of these approaches heavily depend on the underlying network features and use network information to detect the virality of cascades. In most...
Conference Paper
Online activity is characterized by regularities such as diurnal and weekly patterns, reflecting human circadian rhythms and work and leisure schedules. Using data from the online social networking site Facebook, we uncover temporal patterns at a much smaller time scale: within individual sessions. Longer sessions have different characteristics tha...
Article
In this paper we analyze the time series of 12,000+ networks of traders in the e-mini S&P 500 stock index futures contract and empirically link network variables with financial variables more commonly used to describe market conditions. We show that network variables lead trading volume, intertrade duration, effective spreads, trade imbalances and...
Conference Paper
When people share updates with their friends on Facebook they have varying expectations for the feedback they will receive. In this study, we quantitatively examine the factors contributing to feedback expectations and the potential outcomes of expectation fulfillment. We conducted two sets of surveys: one asking people about their feedback expecta...
Conference Paper
In this work we investigate the use of behavior feasibility to adapt and personalize lifestyle-targeting recommender systems for the prevention and treatment of hypertension. Based on survey data (N=300) we model the feasibiliy of 63 behaviors through a Rasch model, describing the engagement in a behavior as a function of the behavior's difficulty...
Conference Paper
Moving to a new country can be difficult, but relationships made there can ease the integration into the new environment. The social ties can be formed with different groups: compatriots from their home country, people originally from their new country (locals), and also immigrants from other countries. Yet very little research on immigration has a...
Conference Paper
The asynchronous nature of communications on social network sites creates a unique opportunity for studying how posting content interacts with individuals' engagement. This study focuses on the behavioral changes occurring hours before and after contribution to better understand the changing needs and preferences of contributors. Using observationa...
Conference Paper
Cascades of information-sharing are a primary mechanism by which content reaches its audience on social media, and an active line of research has studied how such cascades, which form as content is reshared from person to person, develop and subside. In this paper, we perform a large-scale analysis of cascades on Facebook over significantly longer...
Conference Paper
Social networks readily transmit information, albeit with less than perfect fidelity. We present a large-scale measurement of this imperfect information copying mechanism by examining the dissemination and evolution of thousands of memes, collectively replicated hundreds of millions of times in the online social network Facebook. The information un...
Article
Cascades of information-sharing are a primary mechanism by which content reaches its audience on social media, and an active line of research has studied how such cascades, which form as content is reshared from person to person, develop and subside. In this paper, we perform a large-scale analysis of cascades on Facebook over significantly longer...
Article
Full-text available
Exposure to news, opinion and civic information increasingly occurs through social media. How do these online networks influence exposure to perspectives that cut across ideological lines? Using de-identified data, we examined how 10.1 million U.S. Facebook users interact with socially shared news. We directly measured ideological homophily in frie...
Article
Full-text available
Apps are emerging as an important form of on-line content, and they combine aspects of Web usage in interesting ways --- they exhibit a rich temporal structure of user adoption and long-term engagement, and they exist in a broader social ecosystem that helps drive these patterns of adoption and engagement. It has been difficult, however, to study a...
Conference Paper
Full-text available
In March of 2013, 3 million Facebook users changed their profile picture to one of an equals sign to express support of same-sex marriage. We demonstrate that this action shows complex diffusion characteristics congruent with threshold models, with most users observing several of their friends changing their profile picture before taking the action...
Conference Paper
This presentation will describe methods employed for automatic mining of information from large-scale social networks. She will in particular talk about data mining techniques to determine the manner in which news are spread in such networks, what makes messages go viral and what are the characteristics of users that help spread such information. H...
Conference Paper
Vast amounts of information are propagated in online social networks such as Facebook. This talk will describe several studies characterizing how information diffuses over social ties, from the growth of individual cascades to the predictability of their eventual size. It will also characterize the diffusion of specific kinds of information, includ...
Conference Paper
Full-text available
The Gartner's 2014 Hype Cycle released last August moves Big Data technology from the Peak of Inflated Expectations to the beginning of the Trough of Disillusionment when interest starts to wane as reality does not live up to previous promises. As the hype is starting to dissipate it is worth asking what Big Data (however defined) means from a scie...
Article
Online social networks provide a rich substrate for rumor propagation. Information received via friends tends to be trusted, and online social networks allow individuals to transmit information to many friends at once. By referencing known rumors from Snopes.com, a popular website documenting memes and urban legends, we track the propagation of tho...
Article
Full-text available
In this paper we present the first large-scale empirical study of how visually impaired people use online social networks, specifically Facebook. We identify a sample of 50K visually impaired users, and study the activities they perform, the content they produce, and the friendship networks they build on Facebook. We find that visually impaired use...
Article
Full-text available
On many social networking web sites such as Facebook and Twitter, resharing or reposting functionality allows users to share others' content with their own friends or followers. As content is reshared from user to user, large cascades of reshares can form. While a growing body of research has focused on analyzing and characterizing such cascades, a...
Article
Social networks readily transmit information, albeit with less than perfect fidelity. We present a large-scale measurement of this imperfect information copying mechanism by examining the dissemination and evolution of thousands of memes, collectively replicated hundreds of millions of times in the online social network Facebook. The information un...
Conference Paper
Social media question asking, in which people use Internet technologies to solicit help from other people, is an increasingly common way for people to find information. This workshop brings together researchers studying social media question asking from a variety of perspectives, including social scientists seeking to understand and describe the ph...
Conference Paper
Full-text available
When users post photos on Facebook, they have the option of allowing their friends, followers, or anyone at all to subsequently reshare the photo. A portion of the billions of photos posted to Facebook generates cascades of reshares, enabling many additional users to see, like, comment, and reshare the photos. In this paper we present characteristi...
Chapter
Glossary Definition of the Subject Introduction Graph Structure Algorithms Subsets of the Web Graph Future Directions Bibliography
Article
Sentiment is a rich and important dimension of social interaction. However, its presence in computer-mediated communication in corporate settings is not well understood. This paper provides a preliminary study of people's expression of sentiment in email conversations in an organizational context. The study reveals that sentiment levels evolve over...
Article
Full-text available
Online social networking technologies enable individuals to simultaneously share information with any number of peers. Quantifying the causal effect of these technologies on the dissemination of information requires not only identification of who influences whom, but also of whether individuals would still propagate information in the absence of so...
Article
A popular Facebook meme asks a user's friends to recall how they met that user and then to paste the same query in their own status. We study the spread of this particular meme, which engaged millions of Facebook users, and the insights into relationship formation that the resulting compilation of answers provides. We describe the locations, relati...
Article
The recording and sharing of cooking recipes, a human activity dating back thousands of years, naturally became an early and prominent social use of the web. The resulting online recipe collections are repositories of ingredient combinations and cooking methods whose large-scale and variety yield interesting insights about both the fundamentals of...
Conference Paper
Full-text available
Virtual goods continue to emerge in online communities, offering scholars an opportunity to understand how social networks can facilitate the diffusion of innovations. We examine the social ties for over one million user-to-user virtual goods transfers in Second Life, a popular 3D virtual world, and the unique role that groups play in the diffusion...
Article
Hospital-acquired infections with highly resistant organisms are an important problem among critically ill patients. Control of these organisms has largely focused within individual hospitals. We examine the extent to which transfers of critically ill patients could be a vector for the wide spread of highly resistant organisms, and compare the effi...
Article
Full-text available
As individuals communicate, their exchanges form a dynamic network. We demonstrate, using time series analysis of communication in three online settings, that network structure alone can be highly revealing of the diversity and novelty of the information being communicated. Our approach uses both standard and novel network metrics to characterize h...
Article
One mathematical model can account for power-law distributions in a variety of systems. Eschewing system-specific assumptions, it utilizes a shared feature of the observed distributions: they all describe the division of items into groups.
Conference Paper
Significant cultural differences persist between East and West. Software systems that have been proven to operate efficiently within one culture can fail in the context of the other, especially if they are intended to support rich social interactions. In this paper we demonstrate how a virtual currency system, not unlike ones employed by many US-ba...
Conference Paper
Culture shapes interpersonal communication. However, little is known about how culture interacts with computer-mediated communication, CMC) tools in a business context. We present a large-scale empirical study of cultural differences in computer mediated social interactions in a global company. Our dataset includes 9,000 volunteer users and more th...
Conference Paper
Online social networking tools are used around the world by people to ask questions of their friends, because friends pro-vide direct, reliable, contextualized, and interactive respons-es. However, although the tools used in different cultures for question asking are often very similar, the way they are used can be very different, reflecting unique...
Article
To explore the effects of different incentives on crowdsourcing participation and submission quality, we conduct a randomized field experiment on Taskcn, a large Chinese crowdsourcing site using mechanisms with features of an all-pay auction. In our study, we systematically vary the size of the reward as well as the presence of a soft reserve, or e...
Article
As virtual goods continue to proliferate in online worlds, understanding their production, consumption and distribution remains exciting for scholars, technology companies and policy makers alike. We present a descriptive study of the activities of successful sellers in Second Life, a 3D virtual world that allows users to create their content and e...
Article
Social games, being embedded in and drawing upon existing social networks, have the potential to spread virally. In this paper, we examine two popular social games, each having millions of Facebook users, to understand the role that users play individually and collectively in propagating social applications. At the individual level, the users' invi...
Chapter
Help-seeking communities have been playing an increasingly critical role the way people seek and share information online, forming the basis for knowledge dissemination and accumulation. Consider: About.com, a popular help site (http://about.com), boasts 30 million distinct users each month Knowledge-iN, a Korean site (http://kin.naver.com/), has...
Article
This paper examines social structures underlying economic activity in Second Life (SL), a massively multiplayer virtual world that allows users to create and trade virtual objects and commodities. We find that users conduct many of their transactions both within their social networks and within groups. Using frequency of chat as a proxy of tie stre...
Article
User retention is important to the success of online social media, particularly in virtual world settings where users shape one another’s online experience. We study a rich set of variables, including social network and group membership, chatting, and transactions, in order to predict which users will stay and which ones will leave. We find that si...
Article
Retaining participation is crucial for information services, online knowledge sharing services among them. We present the first comprehensive analysis of users’ activity lifespan across three predominant online knowledge-sharing communities. Extending previous work focusing on initial interactions of new users, we use survival analysis to quantify...
Article
We model and measure patterns of order execution in order driven markets. We model these patterns as trading networks - graphs consisting of traders (nodes) and pairwise buy-sell connections among them (edges) that occured within a period of time. We construct a time series of over 12,000 trading networks using audit trail, transaction-level data f...
Article
Full-text available
Before contributing new knowledge, individuals must attain requisite background knowledge or skills through schooling, training, practice, and experience. Given limited time, individuals often choose either to focus on few areas, where they build deep expertise, or to delve less deeply and distribute their attention and efforts across several areas...
Conference Paper
Retaining participation is crucial for information services, online knowledge sharing services among them. We present the first comprehensive analysis of users' activity lifespan across three predominant online knowledge sharing communities. Extending previous work focusing on initial interactions of new users, we use survival analysis to quantify...
Article
We find that ratings are not absolute, but rather depend on whether they are given anonymously or under one's own name and whether they are displayed publicly or held confidentially. The potential to reciprocate produces higher and more correlated ratings than when individuals are unable to see how others rated them. Ratings further depend on the g...
Conference Paper
User retention is important to the success of online social media, particularly in virtual world settings where users shape one another's online experience. We study a rich set of variables, including social network and group membership, chatting, and transactions, in order to predict which users will stay and which ones will leave. We find that si...
Article
Full-text available
We apply network analysis to trace patterns of information transmission in an elec- tronic limit order market. If market orders or large executable limit orders are submitted by informed traders, then resulting star-shaped or diamond-shaped patterns - or trading networks - should be associated with large changes in returns, smaller volume, and shor...
Data
Average $p_{ij}$ between communities over time. (0.24 MB EPS)
Conference Paper
Full-text available
Social influence determines to a large extent what we adopt and when we adopt it.This is just as true in the digi- tal domain as it is in real life, and has become of increas- ing importance due to the deluge of user-created content on the Internet. In this paper, we present an empirical study of user-to-user content transfer occurring in the conte...
Conference Paper
Online, hyperlinks connect not just related information, but people who relate to one another. In this talk I will discuss the many dimensions and uses of the social hyperlink across a variety of online communities. Sometimes it is the information that brings the people together, as they are seeking answers to questions, or seeking to answer questi...
Article
Full-text available
The paper citation network is a traditional social medium for the exchange of ideas and knowledge. In this paper we view citation networks from the perspective of information diffusion. We study the structural features of the information paths through the citation networks of publications in computer science, and analyze the impact of various citat...
Conference Paper
Large general-purposed community question-answering sites are becoming popular as a new venue for generating knowledge and helping users in their information needs. In this paper we analyze the characteristics of knowledge generation and user participation behavior in the largest question-answering online community in South Korea, Naver Knowledge-i...
Article
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A field is emerging that leverages the capacity to collect and analyze data at a scale that may reveal patterns of individual and group behaviors. Government Version of Record
Article
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Human knowledge and innovation are recorded in two media: scholarly publication and patents. These records not only document a new scientific insight or new method developed, but they also carefully cite prior work upon which the innovation is built. We quantify the impact of information flow across fields using two large citation dataset: one span...
Conference Paper
Full-text available
This paper describes our approach to assured information sharing. The research is being carried out under a MURI 9Multiuniversity Research Initiative) project funded by the air force office of scientific research (AFOSR). The main objective of our project is: define, design and develop an assured information sharing lifecycle (AISL) that realizes t...
Article
Online networks occupy an increasingly larger position in how we acquire information, how we communicate with one another, and how we disseminate information. Frequently, small sets of vertices dominate various graph and statistical properties of these networks and, because of this, they are relevant for structural analysis and efficient algorithms...
Conference Paper
Reputation mechanisms are essential for online transactions, where the parties have little prior experience with one another. This is especially true when transactions result in offline interactions. There are few situations requiring more trust than letting a stranger sleep in your home, or conversely, staying on someone elsepsilas couch. Couchsur...
Conference Paper
Witkeys are a thriving type of web-based knowledge sharing market in China, supporting a form of crowdsourcing. In a Witkey site, users offer a small award for a solution to a task, and other users compete to have their solution selected. In this paper, we examine the behavior of users on one of the biggest Witkey websites in China, Taskcn.com. On...
Conference Paper
Full-text available
Online networks occupy an increasingly larger position in how we acquire information, how we communicate with one another, and how we disseminate information. Frequently, small sets of vertices dominate various graph and statistical properties of these networks and, because of this, they are relevant for structural analysis and efficient algorithms...
Conference Paper
Full-text available
Blogs, wikis, tagging, podcasts, and social networking websites such as MySpace, Facebook, Flickr and YouTube have radically changed user interactions on the World Wide Web from a static, one-way, consumption model to a dynamic, multi-way, participation model. Broad user power and flexibility have changed how people engage in and experience their i...
Conference Paper
Full-text available
Yahoo Answers (YA) is a large and diverse question-answer forum, acting not only as a medium for sharing technical knowledge, but as a place where one can seek advice, gather opinions, and satisfy one's curiosity about a countless num- ber of things. In this paper, we seek to understand YA's knowledge sharing activity. We analyze the forum categori...
Conference Paper
Witkeys" are websites in China that form a rapidly growing web- based knowledge market. A user who posts a task also offers a small fee, and many other users submit their answers to compete. The "Witkey" sites fall in-between aspects of the now-defunct Google Answers (vetted experts answer questions for a fee) and Yahoo Answers (anyone can answer o...
Conference Paper
Help-seeking communities have been playing an increasingly critical role in the way people seek and share information. However, traditional help-seeking mechanisms of these online communities have some limitations. In this paper, we describe an expertise-finding mechanism that attempts to alleviate the limitations caused by not knowing users' exper...
Article
Full-text available
Information on any given topic is often scattered across the Web. Previously this scatter has been characterized through the inequality of distribution of facts (i.e. pieces of information) across webpages. Such an approach conceals how specific facts (e.g. rare facts) occur in specific types of pages (e.g. fact-rich pages). To reveal such regulari...
Conference Paper
Web-based communities have become important places for people to seek and share expertise. We find that networks in these communities typically differ in their topology from other online networks such as the World Wide Web. Systems targeted to augment web-based communities by automatically identifying users with expertise, for example, need to adap...