Top 10 Social Networking Websites & Forums - December 2009

Note: The Hitwise data featured is based on US market share of visits as defined by the IAB, which is the percentage of online traffic to the domain or category, from the Hitwise sample of 10 million US internet users. Hitwise measures more than 1 million unique websites on a daily basis, including sub-domains of larger websites. Hitwise categorizes websites into industries on the basis of subject matter and content, as well as market orientation and competitive context. The market share of visits percentage does not include traffic for all sub-domains of certain websites that could be reported on separately.