In the month of June 2011 Facebook reached 1 trillion page views. The 1 trillion views came from 870 million different people – Facebook claims only 750 million users, but it is possible to access parts of the site without being a member. That’s because many of the site’s pages come up in search results and are generally visible to non-users, if only partially.
The second most-visited website was YouTube, which had 790 million unique visitors in June and 100 million pageviews.
The data released by DoubleClick does not include adult websites, ad networks and certain sites owned by Google.