I just use it for keeping up to date on what my friends are doing, and let them keep up to date on what I'm doing (assuming they care). I don't play games, or use any apps, or anything like that.
Occasionally there are some interesting topics posted which generate a lot of conversation - conversations we probably would have in person if we were together, but we have them on Facebook because it's more immediate. You can talk about something right away rather than waiting a few weeks until the next time we see each other.
Right now, I have 635 friends (though some of them are accounts that have been deactivated, so it's probably closer to 625). They tend to fall into four major categories:
- people I know through fandom
- people I know through this place (which is, I suppose, a subset of fandom)
- people I went to school with (mostly university and high school, though there are a few who predate high school)
- people I know through other random activities (such as the bowling league I belong to), people I was friends with on Livejournal when I used it, etc.
I have very few friends who don't fall into any of these categories, and they tend to be people who have sent me friend requests and they seemed harmless enough, so I accepted them.
Every once in a while, though, I get a friend request that just confuses me. Usually they're from authors with whom I have several mutual friends, but I'm not sure why they're friending me. It's not as though they're likely to have heard of me (though I've certainly heard of them). Not that I'm complaining, because it's interesting to keep up on what they're working on.