Granted this is a ruling by a judge in Ontario Canada so chances are the rest of the world will probably give out a big YAWN along with a who cares but it is interesting to see the judge's reasoning for her opinion. It involves civil litigation suit due to a vehicle accident where the judge ordered one of the parties involved to hand over the contents of their private Facebook account.
The judge's opinion (via Michael Geist)
a court can infer from the social networking purpose of Facebook, and the applications it offers to users such as the posting of photographs, that users intend to take advantage of Facebook's applications to make personal information available to others. From the general evidence about Facebook filed on this motion it is clear that Facebook is not used as a means by which account holders carry on monologues with themselves; it is a device by which users share with others information about who they are, what they like, what they do, and where they go, in varying degrees of detail. Facebook profiles are not designed to function as diaries; they enable users to construct personal networks or communities of "friends" with whom they can share information about themselves, and on which "friends" can post information about the user.
[picture courtesy of Top Tech News]