Name Description/Focus Date launched Registered users Registration Global Alexa[1]Page ranking
Facebook General. February 2004 800,000,000+[82] Open to people 13 and older 2[83]
Qzone General. In Simplified Chinese; caters for mainland China users 480,000,000[246][247] Open to the general public NA (Alexa only records data for second-level domains)
Habbo General for teens. Over 31 communities worldwide. Chat Room and user profiles. 200,000,000[130][131][132] Open to people 13 and older 6,545[133]
Twitter General. Micro-blogging, RSS, updates July 15, 2006 175,000,000[298][299] Open 9[300]
Renren Significant site in China. Was known as ?? (Xiaonei) until August 2009. 160,000,000[251] Open 83[252]
Windows Live Spaces Blogging (formerly MSN Spaces) 120,000,000[320] Open NA (Alexa only records data for second-level domains)
LinkedIn Business and professional networking May 2003 120,000,000[171] Open to people 18 and older 13[172]
Bebo General July 2005 117,000,000[15] Open to people 13 and older 2,279[16]
Vkontakte Social Network for Russian-speaking world including former Soviet republics. September 2006 110,578,500[301] Open 44[302]
Tagged General. 100,000,000[279] Open 281[280]
Orkut General. Owned by Google Inc. Popular in India and Brazil.[227] January 22, 2004 100,000,000[228] Open to people 18 and older, (Google login) 106[229]
Myspace General August 2003 100,000,000+[204][205] Open to ages 13 and older. 86[206]

For more information, please visit: Wikipedia