because I'm always behind on these web 2.0 things
I'm sure there must be a LibraryThing for music collections somewhere, so that you can tag your music to search for stuff, browse your friends' music tastes, rec things, and all that social network stuff. Especially considering that somehow exporting music collection lists from media players has to be easier than to input books. But somehow I haven't seen people link to anything like that for sharing lists of their music collections online yet. So where is that site, or which is most popular if there are several?