the problem with Last.fm

I'm putting on my web dork hat now. You have been warned.
Last.fm is a cool new radio site. It's cool because of the associated plugin, called Audioscrobbler, that sits silently on your computer and makes a profile of your listening tastes based on what music you play. So far so good. Then Last.fm takes this data and tells you what other listeners (your 'neighbours') share your taste in music, and thereby you can discover other new music that you would probably like. Excellent. So over time, based on my taste in music, I get a virtual collection of music.
I have been playing with this system for some days now, and I have many problems with it. First, mainly because I have been listening to a lot of world music, there is no match higher than 40%. And most of these neighbors have some music in their profiles that I absolutely cannot stand. So If I, say, listen to somebody else's profile radio, I get to hear a lot of junk that I have to keep skipping or banning. However, if I don't do so, the artist/song is logged on my profile and then I become more like the neighbor. And the more I let the site do this, the more universal my profile radio is going to sound. To take it to the logical extreme, everybody's profile will start sounding like everybody else's.
So if I disable the logging of other profiles's songs (which kind of defeats the purpose, even Yahoo's Launchcast would be as good), I end up with a radio station that kinda sorta plays the music I like. Which is good I guess, but there are hundreds of radio stations that already do that. I guess I agree with Zephoria in that Last.fm has really no procedure for moods or genres. I think they really could do with a cool tagging system. It's primarily a method to discover new music and to connect with people who might share your taste, but I wonder if that warm, fuzzy feeling you get by connecting with musically alike strangers is worth the pain and hassle of skipping/banning stuff you don't like.