I haven't fully explored this yet, and although it's in its infancy, so there are inevitably flaws to it, it's certainly a great idea.
It all stems from the Music Genome Project, something that's been going on for the past 5 years, which aims to be the most comprehensive analysis of music ever. It basically involves a staff of dozens of professional musicians who analyse songs and try to map the genome of music - all the various attributes or genes that make up all the types of music and songs that exist - and then group songs together that share the same 'genes'.
The idea is that this method of comparing songs serves as a more accurate way of being able to predict what new music an individual will like. If you like a certain song, there's a good chance that a song that has similar 'genes' will also float your boat.
It should prove to be a far better music recommendation tool than that found on Amazon and similar websites, which simply looks at the buying habits of individuals. It's a fairly safe bet that if someone buys one album by Frank Zappa they would also buy another album by Frank Zappa. That's not very helpful advice when you're looking for new music.
This Pandora malarkey, as it's known (not the malarkey bit), has a library of 300,000 songs from 10,000 artists covering pretty much all music except Classical and World, and works in the format of a radio station, where the playlist is governed by what you define as the songs or artists that you like. As in the Amazon recommendations, you can fine-tune the playlist by assessing how appropriate any song played is to your tastes.
I'm just checking-out the trial version now and it ain't all bad. It's a bit odd though that if you state Queen as an artist you like, you get a handful of Queen songs in the playlist...But apart from that I've heard some great tunes from artists I've never heard of so far which is what it's all about.
I've just realised that this sounds like a shameless plug for the website. It isn't. I was bored and wanted to share my discovery.
Oh yeah, the link: http://www.pandora.com
Gullibility and credulity are considered undesirable qualities in every department of human life -- except religion.