Having friends on Facebook is about the same as having friends (or relatives) in real life. Meaning you don't want to contact various people and have relationships with them -- at least I don't -- if you don't know them. That seems pointless.
Of course how do you ever get to know new people if you don't occasionally reach out? Except the way that works in real life is that you see each other, you have mutual interests, and it happens more or less organically. On the internet you might have mutual interests and see someone's picture, but there's very little of an organic nature that's going to happen ... unless you're in an IRC group, chat room or something. And even then I'm more likely to be wary.
I have a painting by a guy, and I looked him up on Facebook, and sure enough, there he was. Not a fan page, which I might very well join were there one. But his own page. To be "friends" with him, even with my proud possession of his painting, seems pointless. Because what is he going to say? Who is this guy? What do I care what time he got up? Whether he's disabled, has a game toe or whatever? He wouldn't care about that. Really no more than I'd care what he's doing, or how many points he scored on PopAnswers.
So it's not exactly friends territory for making friends.