At the end of 2011 Facebook had 845 million monthly active users, according to IPO filing documents, which an increase of 39% from the end of the previous year. $3.71 billion in income from 2011’s users, averages $4.39 per user. About 483 million Facebookers used the service every day in December 2011, a 48 percent increase from 2010.
Facebook used to publish user-count milestones every 50 million people or so but stopped in recent times. The company sometimes disagreed third parties’ approximated numbers, like those from AppData, which makes estimates from queries of Facebook advertising tools.
Facebook would have one billion users as of August 2012 if current growth patterns continue.