This is always the first thing that comes to mind when i think of Facebook and to this day it still makes me laugh:
I have about 20 or so 'friends' on facebook but they're mostly family/extended family. Anything else is just tedious drama and i'm not wasting my life on it. I have a profile i suppose to keep tabs on family gossip in a free and efficient way lol Can't answer your last question i'm afraid but i'm assuming it's mostly down to a nauseating mix of nostalgia and laziness