A friend of mine related something very interesting to me the other day. We were discussing the relative value of social networking (Facebook, specifically) over email or "more traditional" ways to connect, given Slashdot's post that "email is for old people."
That struck me as wrong since the 12-18-year olds that I know (and I actually know quite a few since I'm involved in several neighborhood youth groups) may not spend most of their communication in email, but they certainly don't spend it in Facebook or MySpace, either. They take a blended approach, just as I do, and communicate with friends according to how close they are:
They tiered their friends: those that they would call, those they would text, those they would email, and everyone else they'd just keep in contact with via Facebook.
Close friends get close communication: phone and texting. Teachers, adults, and some friends get email. Friends out in the "bazaar" get the MySpace/Facebook treatment. No particular tool trumps the other - they're complementary.
As for me, I know that in a given day I'll IM, text, call, email, and even ping on Facebook the same person. It just depends on how immediate I need a response and whether I'm seeking an "intimate" conversation or simply broadcasting.
The opportunity for Facebook and MySpace is to find ways to interweave phone/text/email conversations into the broader Facebook/MySpace conversations, to help boil down the noise to simple, direct, and productive conversations.