A social network service focuses on the building and verifying of online social networks for communities of people who share interests and activities, or who are interested in exploring the interests and activities of others, and which necessitates the use of software.
Most social network services are primarily web based and provide a collection of various ways for users to interact, such as chat, messaging, email, video, voice chat, file sharing, blogging, discussion groups, and so on.
The main types of social networking services are those which contain directories of some categories (such as former classmates), means to connect with friends (usually with self-description pages), and recommender systems linked to trust. Popular methods now combine many of these, with MySpace, Bebo and Facebook being the most widely used in the anglosphere and Friendster being the most widely used in Asia.
There have been some attempts to standardize them (see the FOAF standard) but this has led to some privacy concerns.
The notion that individual computers linked electronically could form the basis of computer mediated social interaction and networking was suggested early on - for example The Network Nation by S. Roxanne Hiltz and Murray Turoff (Addison-Wesley, 1978, 1993) effectively sketched out how computer-mediated communication -- such as the Internet -- should be developed for this purpose.
There were many early efforts to support social networks via computer-mediated communication, including Usenet, bulletin board services (BBS), Arpanet, and EIES: Murray Turoff's server-based Electronic Information Exchange Service (Turoff and Hiltz, 1978, 1993). The Information Routing Group developed a schema about how the proto-Internet might support this.
Early social networking websites included Classmates.com (1995), focusing on ties with former school mates, SixDegrees.com (1997), focusing on indirect ties, and CaringBridge.org (1997), connecting family and friends during a critical llness, treatment or recovery. Two different models of social networking that came about in 1999were trust-based, developed by Epinions.com, and friendship-based, such as those developed by Jonathan Bishop and used on some regional UK sites between 1999 and 2001. Innovations included not only showing who is "friends" with whom, but giving users more control over content and connectivity. By 2005, one social networking service MySpace, was reportedly getting more page views than Google, with Facebook, a competitor, rapidly growing in size. In 2007, Facebook began allowing externally-developed add-on applications, and some applications enabled the graphing of a user's own social network -- thus linking social networks and social networking.
Social networking began to flourish as a component of business internet strategy at around March 2005 when Yahoo launched Yahoo! 360°. In July 2005 News Corporationbought MySpace, followed by ITV (UK) buying Friends Reunited in December 2005. It is estimated that combined there are now over 200 social networking sites using these existing and emerging social networking models.
Social networks connect people at low cost; this can be beneficial for entrepreneurs and small businesses looking to expand their contact base. These networks often act as a customer relationship management tool for companies selling products and services. Companies can also use social networks for advertising in the form of banners and text ads. Since businesses operate globally, social networks can make it easier to keep in touch with contacts around the world. In many ways business networking on social networks has eclipsed the amount of networking that takes place on dedicated business networking websites.
Social networks are beginning to be adopted by healthcare professionals as a means to manage institutional knowledge, disseminate peer to peer knowledge and to highlight individual physicians and institutions. The advantage of using a dedicated medical social networking site is that all the members are screened against the state licensing board list of practitioners.
The role of social networks is especially of interest to pharmaceutical companies who spend approximately "32 percent of their marketing dollars" attempting to influence the opinion leaders of social networks.
In contrast, CaringBridge is a nonprofit organization offering free personalized websites to people in a health care crisis, hospitalization, undergoing medical treatment and/or recovering from a significant medical condition or procedure. Its functionality is similar to a blog. The service allows family members and friends to receive consistent information via a single website, and eliminates the need to place and receive numerous telephone calls. CaringBridge is the largest (for traffic) charitable nonprofit website in the world. By the end of 2007, more than 90,000 people have created a CaringBridge website. In total, those websites have received over a half a billion visits and 13 million written guestbook messages of love, hope and support.
Languages, nationalities and academia
Various social networking sites have sprung up catering to different languages and countries. The popular site Facebook has been cloned for various countries and languages and some specializing in connecting students and faculty.