I became aware of Danah Boyd's research a few years ago when I somehow stumbled over one of her papers discussing social networking sites. Since that time Danah Boyd has joined MSR and more recently she gave a couple of interesting talks about privacy at SXSW and at Microsoft TechFest. The transcripts of these talks can be accessed from her site:

Making Sense of Privacy and Publicity - SXSW talk
Privacy, Publicity, and Visibility - TechFest talk

Privacy matters.