Danah Boyd has a great post about privacy and Facebook including the following question:
apophenia: Putting Privacy Settings in the Context of Use (in Facebook and elsewhere)
Why are privacy settings still an abstract process removed from the context of the content itself? Privacy settings shouldn’t just be about control; they should be about the combination of awareness, context, and control. You should understand the visibility of an act during the moment of the act itself and whenever you are accessing the tracings of the act.