58m people accessed Facebook only my mobile in December 2011

"The company has revealed that, during December 2011, more than 58 million Facebook users accessed the social network using their mobile phone only. That’s right, more than 50 million people entered through the service a mobile app or (most likely) their mobile browser, without logging in through a PC at all during the month.
Though the number represents a mere 13 percent of the reported 432 million users that were active on a mobile at any point during the month, and even less of its entire 850 million plus userbase, it is a quite incredible statistic. Importantly, it is also one that will continue to rise for two main reasons."
Source:  TheNextWeb, 8th March 2012