Online dating sites frequently claim that they have fundamentally altered the dating landscape for the better. This article employs psychological science to examine (a) whether online dating is fundamentally different from conventional offline dating and (b) whether online dating promotes better romantic outcomes than conventional offline dating. The answer to the first question (uniqueness) is yes, and the answer to the second question (superiority) is yes and no. To understand how online dating fundamentally differs from conventional offline dating and the circumstances under which online dating promotes better romantic outcomes than conventional offline dating, we consider the three major services online dating sites offer: access, communication, and matching. Access refers to users' exposure to and opportunity to evaluate potential romantic partners they are otherwise unlikely to encounter. Communication refers to users' opportunity to use various forms of computer-mediated communication (CMC) to interact with specific potential partners through the dating site before meeting face-to-face. Matching refers to a site's use of a mathematical algorithm to select potential partners for users. Regarding the uniqueness question, the ways in which online dating sites implement these three services have indeed fundamentally altered the dating landscape. In particular, online dating, which has rapidly become a pervasive means of seeking potential partners, has altered both the romantic acquaintance process and the compatibility matching process. For example, rather than meeting potential partners, getting a snapshot impression of how well one interacts with them, and then slowly learning various facts about them, online dating typically involves learning a broad range of facts about potential partners before deciding whether one wants to meet them in person. Rather than relying on the intuition of village elders, family members, or friends or to select which pairs of unacquainted singles will be especially compatible, certain forms of online dating involve placing one's romantic fate in the hands of a mathematical matching algorithm. Turning to the superiority question, online dating has important advantages over conventional offline dating. For example, it offers unprecedented (and remarkably convenient) levels of access to potential partners, which is especially helpful for singles who might otherwise lack such access. It also allows online daters to use CMC to garner an initial sense of their compatibility with potential partners before deciding whether to meet them face-to-face. In addition, certain dating sites may be able to collect data that allow them to banish from the dating pool people who are likely to be poor relationship partners in general. On the other hand, the ways online dating sites typically implement the services of access, communication, and matching do not always improve romantic outcomes; indeed, they sometimes undermine such outcomes. Regarding access, encountering potential partners via online dating profiles reduces three-dimensional people to two-dimensional displays of information, and these displays fail to capture those experiential aspects of social interaction that are essential to evaluating one's compatibility with potential partners. In addition, the ready access to a large pool of potential partners can elicit an evaluative, assessment-oriented mindset that leads online daters to objectify potential partners and might even undermine their willingness to commit to one of them. It can also cause people to make lazy, ill-advised decisions when selecting among the large array of potential partners. Regarding communication, although online daters can benefit from having short-term CMC with potential partners before meeting them face-to-face, longer periods of CMC prior to a face-to-face meeting may actually hurt people's romantic prospects. In particular, people tend to overinterpret the social cues available in CMC, and if CMC proceeds unabated without a face-to-face reality check, subsequent face-to-face meetings can produce unpleasant expectancy violations. As CMC lacks the experiential richness of a face-to-face encounter, some important information about potential partners is impossible to glean from CMC alone; most users will want to meet a potential partner in person to integrate their CMC and face-to-face impressions into a coherent whole before pursuing a romantic relationship. Regarding matching, no compelling evidence supports matching sites' claims that mathematical algorithms work-that they foster romantic outcomes that are superior to those fostered by other means of pairing partners. Part of the problem is that matching sites build their mathematical algorithms around principles-typically similarity but also complementarity-that are much less important to relationship well-being than has long been assumed. In addition, these sites are in a poor position to know how the two partners will grow and mature over time, what life circumstances they will confront and coping responses they will exhibit in the future, and how the dynamics of their interaction will ultimately promote or undermine romantic attraction and long-term relationship well-being. As such, it is unlikely that any matching algorithm that seeks to match two people based on information available before they are aware of each other can account for more than a very small proportion of the variance in long-term romantic outcomes, such as relationship satisfaction and stability. In short, online dating has radically altered the dating landscape since its inception 15 to 20 years ago. Some of the changes have improved romantic outcomes, but many have not. We conclude by (a) discussing the implications of online dating for how people think about romantic relationships and for homogamy (similarity of partners) in marriage and (b) offering recommendations for policymakers and for singles seeking to make the most out of their online dating endeavors.