Of course I have a facebook.
And of course I don't go spamming it around every forum I'm on. That isn't, as far as I can tell, and certainly as far as I'm concerned, what it's for. I use it to keep up with people I actually know. If I want to talk to someone on a forum ... I'll talk to them on the forum. If for some other reason we've become better friends (generally this involves actually meeting face to face at some point, as I have done e.g. with people at car owners' club events) then I may invite them as an FB friend or give them my IM link etc. Most I might do before that is my email address or something.
There's an awful lot of nutters and spammers out there, and but a few shining diamonds in amongst it all who are worthy of your precious time.
Besides, monkeysphere. My brain can only keep up with maybe 200 active contacts at the very most - science fact. At least half of them are people without a facebook or even a computer in some cases. So my FB friend count floating somewhere below 100 doesn't seem all that bad. The amount of status updates alone from that is insane and is hard to actually pay masses of attention to.