ComputerWorld: Despite growing privacy concerns, an astonishing 540 million Internet users worldwide visited Facebook in April 2010, or 35.2% of the entire population of Web users, according to new data from Google. Even more incredibly, those users clicked on 570 billion Facebook pages in April, a number eight times larger than Facebook's nearest competitor.
this data excludes Google and youtube and gmail but it is scary none the less. but I see facebook coming to its peak by 2011 Q1.