The basic flaw of MP3.com (too many artists, not enough talent) becomes evident to all but the least discriminating listener on first visit. The pop pap available can only lead to the eventual failure of the site, as who but the download traders and others hoping to receive financial compensation would ever sit through the dregs offered up on their charts? Sure, you can theoretically pick out what genre you're most interested in, but those distinctions are made by the artists and are often flawed in the attempt to give themselves maximum exposure. And who has the time to sort through the thousands of deserving bands that may very well exist deep below the radar of the charts? I don't have a pipe fat enough to waste my day downloading only to hear another Matchbox 20 knockoff.
Which brings the conclusion that MP3.com can't possibly be for the audience of music fans that it purports, otherwise it would strive not to alienate them like a third-rate cousin of Billboard. Though the "new media" pats itself on the back for a musical revolution fomented through Napster et al., the proletariat of music lovers is just as screwed by the current options available on the Internet as they are on the radio, though at different ends of the spectrum. On the radio, the playlist is likely 20 songs deep and chock full of overmarketed crap. On the Internet, the playlist is 20,000 songs deep and chock full of ego-fed crap, with no sense of self-editing.
Until there is some serious Internet music journalism, I'll find my tunes the old-fashioned way -- chatting with my fellow geeks down at the used record store.