I feel the same way about facebook and the like as I would about everyone in the world suddenly developing telepathic abilities. It'd be great at first, but eventually it would spell our outright dissolution as a society. If we all knew enough despicable things about each other, it would be enough make everyone want to start a war!
Of course, as a promotional tool it's great, but if you have nothing to promote and aren't involved with a group that depends on social networking to operate (school, work, criminal organization, etc.), seriously, what are you doing there? I truly believe 95% of all social networking accounts could be permanently deleted with absolutely no repercussions to the world at large. If you need to know what I'm having for lunch, pick up the phone. I'll tell you. If you don't have my phone number, why the hell do you want to know that?! Why the hell do you want to know that, even if you DO have my number? Will you stop calling me and asking me what I'm having for lunch already? I really never should have given you my number. Jesus.
PS: No offense to those of you who like it. I'm a crank! Go in peace and network your hearts out. I'll be here training carrier pigeons to mail things for me.