BitTorrent

From OpenSource

BitTorrent is a peer-to-peer file distribution protocoll. It works by breaking a file up into pieces and then distributing them. that way a client doesn't have to download all the pieces from the same mahine.

The reference implementation is the official BitTorrent Client.

[edit] Legal Status

Because there is no central server BitTorrent has avoided the legal problems that faced napster. It also helps that there is legal content available such as linux distributions