I'm already a member of a music community site, although I didn't join it to meet people. Emusic is a subscriber downloads site which takes advantage of the enormous enthusiasm people have for recommending music to each other. New, old, obscure, you name it, they have a (certain subsection of) it, although being both DRM free and 100% legal leaves their product prone to winking on and off like solar lights in the rain. Another friend on the service finds this intensely aggravating, but I'm more amused; with the amount of music available I'm never going to run out of new, interesting things to download, so the only loss is to the labels. And to emusic, of course -- who should really rename their "save for later" function to "you can save it for later but it may not be available then, are you sure?".
Two, if you count myspace. I suppose that I should. But actually, I'm hitting LastFM today. A site so oldschool, you have to download software for full functionality. No hitches with that, though, so all's good. I figure out scrobbling, build a profile, and set up a suitable soundtrack to go looking for people I already know by. Here, though, is where I hit a snag. It defaults to stealing my address book and spamming all my friends with an "invite". Nah, I don't think so. So I mince through my own address book and pick out the LastFM users by hand, and it's tricky enough that they clearly just want me to give up and just do the spam thing. I also skip over the people who I've drifted out of touch with, those whose email addresses don't instantly recall their name and those who are just a bit too famous. Nah, I'm not going to meet anyone here.
That said, though, it does the music stuff really sweetly. Right now it's pissing down with rain, I'm feeling kind of grim and playing artists similar to Radiohead. I've already had to express my love for tracks twice.
Verdict : It's about the music, not the socialising. Which is fine.