Wikipedia
Social network service
A social network service focuses on building online communities of people who share interests and/or activities, or who are interested in exploring the interests and activities of others. Most social network services are web based and provide a variety of ways for users to interact, such as e-mail and instant messaging services.
The main types of social networking services are those which contain category divisions (such as former school-year or classmates), means to connect with friends (usually with self-description pages) and a recommendation system linked to trust. Popular methods now combine many of these, with Facebook and Twitter widely used worldwide; MySpace and LinkedIn being the most widely used in North America;"adweek"> - 66% of MySpace and Facebook users come from North America: Adweek website. Retrieved on January 15 2008. Nexopia (mostly in Canada); Bebo, - most popular of its kind in UK,(August 2007): TechCrunch website. Retrieved on January 15 2008. Hi5, StudiVZ (mostly in Germany), iWiW (mostly in Hungary), Tuenti (mostly in Spain), Decayenne, Tagged, XING;: article from the MarketingVox website., Badoo, Mark Sweney , The Guardian, December 24, 2007 , Accessed March 2008. and Skyrock in parts of Europe;: article from the PBS MediaShift website. Retrieved on January 18 2008. Orkut and Hi5 in South America and Central America; - 55% of users are Brazilian: About.com website. Retrieved on January 15 2008, and Friendster, Mixi, Multiply, Orkut, Wretch, Xiaonei and Cyworld in Asia and the Pacific Islands and Orkut and Facebook in India.
There have been some attempts to standardize these services to avoid the need to duplicate entries of friends and interests (see the FOAF standard and the Open Source Initiative), but this has led to some concerns about privacy.
History
The notion that individual computers linked electronically could form the basis of computer mediated social interaction and networking was suggested early on T read more at » http://en.wikipedia.org/wiki/Social+network+service