Keep in mind, Facebook has been changing privacy settings -- in many cases undoing what people THOUGHT they had already set.
The other side to this story is Facebook has "lost the narrative." That is, we in the media and the general public are talking about Facebook without Facebook's participation.
A number of Facebook alternatives are popping up, the one getting the most press is Diaspora. While these are probably not credible threats, any dotcom should be worried when the supercool urban hipsters start migrating to something else. Case in point, Digg.com.