Schneier's Revised Taxonomy of Social Data

Jamie noted that over at Schneier's blog, he has a worthwhile entry on the data in the social networks. He writes "Lately I've been reading about user security and privacy — control, really — on social networking sites. The issues are hard and the solutions harder, but I'm seeing a lot of confusion in even forming the questions. Social networking sites deal with several different types of user data, and it's essential to separate them."