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.

Below is my taxonomy of social networking data, which I first presented at the Internet Governance Forum meeting last November, and again -- revised -- at an OECD workshop on the role of Internet intermediaries in June.