I enjoy Audioscrobbler, honestly I do. It hasn't really helped me find any bands (but it did help me find out that the Spectral Light... folks had a full album out, through a helpful comment), but it's neat to see what other people are listening to.
In my world, it becomes like a Music Nazi version of MTV's RoomRaiders, in which a bevy of selections can tell me more about you, as a person, than knowing what your bedroom looks like.
That being said, I realize there are serious defects in the system. Like, by basing rankings on the number of songs played, jazz and krautrock get short shrift; there are only two songs on each disc of Bitches Brew and Kraftwerk's Concert Classics only has four, despite being well over an hour long. Bands with more songs per hour necessarily rank higher in profiles (making it hard to find interesting jazz and krautrock without trawling profiles).
But that's not as much fun as just being judgemental about people's musical taste. That's the genius of Audioscrobbler: it works both ways. You can dismiss people as douchbags by what bands they like, and you can take known douchebags and see what they enjoy, and are thus able to dismiss it in the future. It's a beautiful thing.
Take, for example, The Vegetarians, who listen to, say, The Smiths in disproportionate numbers. Has nothing to do with the Meat Is Murder album, right? What else do they listen to (besides the obvious Morrissey)? Well, lots of sissy shit, like you might expect. Radiohead, Elliot Smith, The Cure. Bunch of pantywaists, all slowly rocking from side to side with their mewling mascara-wearing momma's boys (and girls).
Or that the Porn group listens almost exclusively to mainstream metal. Once one has developed a taste for big hair, it pervades every aspect of life.
The Family Guy? More shitty metal, showing that people who appreciate that show enjoy the speed and bombast more than good material (fuckin' Korn? That explains a lot, really.)
But the best are The Furries. The top artists? Less Than Jake, followed by Green Day, Nirvana and 3 Doors Down. What does this tell us about Furries? Well, aside from liking to hump stuffed animals, it tells us that most of them came of age during the early '90s, and haven't let go. Also, that they prize watered-down versions of groundbreaking genres like punk and ska.
To extrapolate, this can be linked with their sexual lives: Instead of going out and really fucking animals, like they'd all love to do, they cop out and fuck people in animal costumes. If, instead, they listed Desmond Dekker, The Buzzcocks and The Pixies, they'd finally have the courage to do some pet damage.
C'mon, Furries, buck up and fuck that horse.