almost 140 million unique visitors per month That seems low. According to http://www.facebook.com/press/info.php?statistics http://www.facebook.com/press/info.

almost 140 million unique visitors per month That seems low. According to http://www.facebook.com/press/info.php?statistics http://www.facebook.com/press/info.php?statistics, it's 800m active users, more than 50% of which log in on any given day.