Most of the MP3s I've downloaded over the years are live, bootlegged or unreleased versions of songs by artists that I really like. So, I was intrigued to read that REM has given its blessing to a file trading network that distributes bootlegs, unreleased and other obscure versions of their songs.
There's a bit of faffing about you have to do to get started--download and configure the WinMX client--but it was pretty straight-forward. And it works as advertised. For example, as I type this, I'm downloading 'What's the Frequency, Kenneth?' from the 1995 concert that I attended. I love it when I find recordings of concerts I've actually been to. I went away disappointed with that show, so now I can see if my feelings were well-founded.
Apparently there are 15 volunteers who monitor the network to remove released, copyrighted material. I did a search for 'Find the River', turning up over a 100 live versions and maybe 10 copies of the album version. That's not bad, but they've got more work to do.
What they should do is implement a voting system, which enables users to vote 'against' copyrighted material. If enough votes were accrued, that file/user/IP would be removed from the network.
UPDATE: Apparently U2 has a similar database at http://www.u2bloodredsky.com/.
Internet Music Technology