I loosely know of Jason Calacanis and don't know what credibilty he has to base these statements on, but it he does raise any interesting point.

What precedent does Facebook have to support the 3rd party developer ecosystem on apps.facebook? /me points at http://developers.facebook.com/docs/api*.

I'd be really interested to see what other HNers have to say about what I think is the main issue: given you don't think becoming a facebook fte is your desired exit strategy, what would you do to protect your IP from Facebook?