Rock groups Phish and the Grateful Dead encourage concert-goers to make recordings of their performances; those large digital files are shared by fans using BitTorrent. Etree.org is a community BitTorrent tracker for sharing live concert recordings of artists that permit their performances to be recorded. You can find recordings of Phish, the Black Crowes, Blues Traveler, the Grateful Dead, Radiohead, and many others through Etree.