We define social network sites as web-based services that allow individuals to (1) construct a public or semi-public profile within a bounded system, (2) articulate a list of other users with whom they share a connection, and (3) view and traverse their list of connections and those made by others within the system. The nature and nomenclature of these connections may vary from site to site.
While we use the term “social network site” to describe this phenomenon, the term “social networking sites” also appears in public discourse, and the two terms are often used interchangeably. We chose not to employ the term “networking” for two reasons: emphasis and scope. “Networking” emphasizes relationship initiation, often between strangers. While networking is possible on these sites, it is not the primary practice on many of them, nor is it what differentiates them from other forms of computer-mediated communication (CMC).
What makes social network sites unique is not that they allow individuals to meet strangers, but rather that they enable users to articulate and make visible their social networks. This can result in connections between individuals that would not otherwise be made, but that is often not the goal, and these meetings are frequently between “latent ties” (Haythornthwaite, 2005) who share some offline connection. On many of the large SNSs, participants are not necessarily “networking” or looking to meet new people; instead, they are primarily communicating with people who are already a part of their extended social network. To emphasize this articulated social network as a critical organizing feature of these sites, we label them “social network sites.”
While SNSs have implemented a wide variety of technical features, their backbone consists of visible profiles that display an articulated list of Friends1 who are also users of the system. Profiles are unique pages where one can “type oneself into being” (Sundén, 2003, p. 3). After joining an SNS, an individual is asked to fill out forms containing a series of questions. The profile is generated using the answers to these questions, which typically include descriptors such as age, location, interests, and an “about me” section. Most sites also encourage users to upload a profile photo. Some sites allow users to enhance their profiles by adding multimedia content or modifying their profile’s look and feel. Others, such as Facebook, allow users to add modules (“Applications”) that enhance their profile.
The visibility of a profile varies by site and according to user discretion. By default, profiles on Friendster and Tribe.net are crawled by search engines, making them visible to anyone, regardless of whether or not the viewer has an account. Alternatively, LinkedIn controls what a viewer may see based on whether she or he has a paid account. Sites like MySpace allow users to choose whether they want their profile to be public or “Friends only.” Facebook takes a different approach—by default, users who are part of the same “network” can view each other’s profiles, unless a profile owner has decided to deny permission to those in their network. Structural variations around visibility and access are one of the primary ways that SNSs differentiate themselves from each other.
After joining a social network site, users are prompted to identify others in the system with whom they have a relationship. The label for these relationships differs depending on the site—popular terms include “Friends,” “Contacts,” and “Fans.” Most SNSs require bi-directional confirmation for Friendship, but some do not. These one-directional ties are sometimes labeled as “Fans” or “Followers,” but many sites call these Friends as well. The term “Friends” can be misleading, because the connection does not necessarily mean friendship in the everyday vernacular sense, and the reasons people connect are varied (boyd, 2006a).