I've been pondering the OpenSocial thing, which I babbled about before.
Take these two techcrunch posts. One: facebook no longer caters to college students. Two: you can "do anything with friends" on Open Social.
This reminds me of an old strategy saw: strategy is about trade-offs, as much about what you don't do as what you do.
Facebook apps and opensocial are all about trying to do "everything" - a hint that there is no strategy. It's still cool, in the way that the Web is cool. ("We invented the Internet - you can do anything on it!") But it's up to every app to define its strategy.
Maybe I'm a weird strategy purist, but I thought that facebook should have stuck to students, and sought its growth through more depth in that area, not breadth. Of course, I'm fairly alone on that opinion and may as well be shouting it off a cliff in Antarctica on that one.