If you look at it just in terms of # of users, of course facebook's offering suffers. But that isn't a great comparison - it's like comparing the # of viewers

If you look at it just in terms of # of users, of course facebook's offering suffers. But that isn't a great comparison - it's like comparing the # of viewers for The Office (awesome show btw) to the total viewers of all TV channels in existence. I think the real win is that their api allows your app to take advantage of the connections between facebook's users.