It's an addiction, yes, but it's also a great way to send out group messages, share funny articles or youtube videos, and keep somewhat in touch with people I only sort of care about...
Who are these people and why are they on my Facebook? They fall into 3 general categories:
1) Old school
We went to elementary/middle/high school/college together. Can't delete them, because we've known each other so long...Yet I haven't seen them in years. I've never met their spouse and/or kids, but I've looked at so many pictures that it feels like I have. Some of their kids are funny-looking, and it's only because we're not "real life" friends that I can admit that. (I'd never say that about a close friend's kids, even if it were true!)
Some people are just hilarious, and even if we're not actually keeping up with each other, I keep them on my Facebook just because they post great stuff. Sometimes they're trying to be funny (i.e. posting a great YouTube video, a quote from a movie, an article from The Onion, etc.), but sometimes I'm just laughing at them. Case in point: a girl from high school who I wasn't really friends with--she requested to add me and the only reason I keep her around is because her posts are unbelievably stupid.
3) Good intentions
There are people in my friends list who I keep meaning to message & catch up with--classmates from study abroad, former co-workers, former teachers, etc. I never really do it, but I wouldn't want to delete them--that would be admitting defeat and resigning to the fact that we're not really friends anymore.
And who do I actually delete? People who post Glenn Beck talking points as updates. That's what it takes to get removed from my friends list ;)