I've been doing a ton of development over here:

http://speakerwiki.org

It's not about prediction, it's about odds. If you don't know the outcome it's better to have 200 possibilities than 1 "great idea."

The only way to beat facebook is to out-open them. Facebook thrives on being a place where users have very tight control over their identities. Watch for something that strips that control from everyone.

This should be required reading everywhere.