Facebook's popularity is based on the reality that human beings are social creatures. Staying connected with people we know is innate to us. But maintaining separate social groups that we don't want to clash is also innate.
In some ways, it's a good thing. Maybe we'd all be a little better off if we could provide a more unified persona to the world. It would be bad if we simply became more private and less authentic, but what if we all just relaxed a little bit about the social norms that cause us to shield big and real parts of ourselves. It's interesting to note which groups we want to self-censor for. Our parents' generation, our workplaces, religious groups. Maybe it's good for everybody if those groups are forced to confront a more accurate picture of our lives.
Obviously I agree with the latter idea, since my entire online persona is tied back to my real name. My website links to my CV right next to my twitter feed filled with snark. In short, I've decided that I won't apologize for who I am.
As a final thought: the world is headed towards a point where everyone has embarrassing pictures online. This is, for all intents and purposes, the same as a world where no one does.