Facebook is the Internet’s largest social network.
Facebook topped 1 billion active users in September 2012 and was the second-most-visited website in the United States, behind Google, as of 2011. Its mobile platform had 874 million active users in 2013. It is also the top source of traffic to the web’s largest portals, such as Yahoo and MSN.
Facebook generated $3.7 billion in revenue in 2011, of which 85% came from advertising. The remainder of its revenue comes from payments, many from game developers using the platform — particularly from Zynga, which was the source of 12% of Facebook’s revenue in 2011. While some revenue had come from virtual goods such as Facebook Gifts, the Facebook Gift Shop closed in August 2010. Facebook first turned a profit in 2009 and made $1 billion in profit in 2011. It went public in May 2012, though its initial public offering was marred by accusations of giving incomplete information to investors, leading to lawsuits from shareholders.
Facebook was founded in 2004 by four Harvard University students led by Mark Zuckerberg, who remains its CEO. Facebook began as a network for Harvard students but expanded to include other colleges in late 2004, high school students in 2005, corporate networks in 2006, and everyone later that year.
Facebook launched its News Feed in 2006, a development for which it submitted a patent application earlier that year and received one in 2010. Several observers have seen the central role of the News Feed, as well as other innovations such as trending topics, as an attempt to co-opt the features of the microblogging platform Twitter. Facebook launched a news aggregation app called Paper in 2014 that relies on a combination of human and algorithmic news selection.
Facebook also has an Open Stream API, which allows third-party developers to use the feed inside their own applications. In 2011, Facebook added a shorter-form feed called Ticker, as well as a more comprehensive profile page called Timeline. It also bought the link-sharing and conversation services Branch and Potluck in 2014.
In 2008, Facebook launched Facebook Connect, which allowed outside sites to extend users’ Facebook login to their own sites. Facebook Connect was folded into Open Graph in April 2010.