Commercial: the Facebook backlash backlash starts here
Naturally it had to happen. So of the knocking pieces on FB, take your pick from the wryly cynical about the privacy aspects; the theoretically bonkers (with added crazy notions such as the idea that you could become famous through FB); and the sullen, codgery one-upmanship - ie 'I write to/call my/see/drink with my friends' etc etc.
But remember: when someone tells you that they don't do 'social networking' because they have a real life and real friends, what they're actually saying is, "I'm a better person than you. Because I value a supposed notion of 'quality' in my relationships. Oh, and I have the time to use more languorous forms of communication. Which must inevitably mean that I'm richer than you too."
For a more optimistic take on the power of social networking and Facebook, see Rory Sutherland's post, which posits a really useful category of communications: "semi-addressable".