For almost 4 months it looked like Facebook might unseat google as the #1 site on the web, in spite of their claimed growth in 'active users' Facebook has not been able to take the top spot, and the weekend swap (when google and facebook would temporarily exchange places as #1 and #2) is no longer happening.
This isn't an argument for our continued relevance or anything, just fixing your figure :)
[0] http://www.scribbal.com/2011/09/facebook-now-has-800-million...