Facebook is an American online social media and social networking service company based in Menlo Park, California.
Friendica (formerly Friendika, originally Mistpark) is open source software for a distributed social network.
Fuelmyblog is a social network for the blogger community that is based in part on interactions facilitated by a web widget that many members install on their blog.
Foursquare is a local search-and-discovery service mobile app which provides search results for its users. The app provides personalized recommendations of places to go to near a user's current location based on users' "previous browsing history, purchases, or check-in history".
Sina Weibo is a Chinese microblogging (weibo) website. Launched by Sina Corporation on 14 August 2009, it is one of the most popular social media sites in China.
Skype is a telecommunications application software product that specializes in providing video chat and voice calls between computers, tablets, mobile devices, the Xbox One console, and smartwatches via the Internet and to regular telephones.
Snapchat is a multimedia messaging app popular in North America and Europe created by Evan Spiegel, Bobby Murphy, and Reggie Brown, former students at Stanford University, and developed by Snap Inc., originally Snapchat Inc.
Skyrock.com is a social networking site based in France that offers a free space on the web to allow its users to create blogs, add profiles, and exchange messages with other registered members.
Twitter is an online news and social networking service where users post and interact with messages, known as "tweets."
Tagged is a social discovery website based in San Francisco, California, founded in 2004. It allows members to browse the profiles of any other members, and share tags and virtual gifts.
Taringa! is a social network geared toward Latin American users.
TermWiki.com is a major social learning network that allows users to learn, discover, share, and store personal terms and glossaries in 1487 domains in 97 languages.