Schadenfreude and just desserts aside, Randi has a good point here. So much of the talk about privacy on social networks overlooks the problem of human nature. Most people won't have their privacy most painfully violated by a service, but by those in their network who carelessly forward their digital communications.
(to clarify: I'm not absolving FB of blame...I'm assuming that just about everyone here agrees that FB's privacy implementation is not great. I'm just saying that Randi's point, even if it was said to deflect responsibility, is true in the larger sense. As we'll find out as Poke w/ pics becomes more popular)