Like quanticle said, social networking. You can't say, "fuck this, I'll just integrate with myspace instead" without getting laughed out of the room. Like it or not, Facebook's the only game in town.
My problem is that is not a real thing which can be monopolized. I promise I'm not being (intentionally) obtuse here. I don't understand which piece of an online offering requires Facebook. Maybe an example would help me.
Specifically with respect to the OP, they have a gigantic datastore of their users' social graphs. That's a "real thing" that can be monopolized: their users' data.
I agree, there's nothing that requires facebook yet, and I hope developers realize the importance of keeping things that way, and stop integrating FB's services while there is still a choice.
