Facebook revealed that its iPhone app has 102.2 million monthly active users, with another 57.5 million using Facebook for BlackBerry, 11.9 million using its Android app, and 2.6 million using its Palm webOS app.
That's already 174.2 million monthly active users, and this figure doesn't include the 986,000 people still using Facebook for Sidekick, the 120,000 people on INQ handsets.
What's more, these figures don't include anyone using Facebook from their Nokia handset - it doesn't have a dedicated application page on Facebook like those listed above. Nor does it include any users accessing the social network through operator or handset UIs (Vodafone 360, Motoblur etc), or through Facebook's mobile website, which is big in the developing world.
In short, Facebook's active mobile user base is surely already over the 200 million mark, and probably well on the way towards 250 million.