The BitTorrent file sharing system must be getting some traction because its inventor, Bram Cohen, has been interviewed in The New York Times (free reg req'd).
As the article notes, BitTorrent is less than ideal for copyright theft: "For his part, Mr. Cohen pointed out that BitTorrent users are not anonymous and that their numeric Internet addresses are easily viewable by anyone who cares. 'It amazes me that sites like Suprnova continue to stay up, because it would be so easy to sue them,' he said. Using BitTorrent for illegal trading, he added, is 'patently stupid because it's not anonymous, and it can't be made anonymous because it's fundamentally antithetical to the architecture'."