The fact that information is more or less publicly available may not be a complete answer to all arguments about privacy. Privacy is about intrusion rather than secrecy and the question is whether you have a reasonable expectation that something is private, rather than whether you have done or said something in public. These concepts are not easy to apply to social networking sites where the point of the exercise is to share information with others.
I think the Guardian is wrong on both the details and the fundamentals. How is a photo from a student Hallowe'en party of an individual who only later entered public life in the "public interest"? How can a desire to share information with friends be translated into a desire to see private photographs published in a newspaper read by millions of people around the world?
We saw a similar plundering of Facebook and Myspace sites after the appalling murder in Perugia last November. Who knows what effect that has had on the potential for a fair trial of the accused, or the lives of those peripherally involved?
As Chris Marsden, Lilian Edwards and I said in our GikII conference paper last summer, the privacy issues raised by social networking sites are far more complex than many in the media would like to believe.