Read about the time I discovered BitTorrent.
According to analysts, BitTorrent traffic today constitutes one-third of internet traffic ! BitTorrent is an amalingly beautiful p2p (peer-to-peer) protocol that helps one to download *huge* files at amzing speeds. What could take hours thru' the famed Kaaza could be done if a few minutes via BitTorrent.
The "philosophy" behind the design is relatively simple (so to say).
The problem with P2P file-sharing networks like Kazaa, he reasoned, is that uploading and downloading do not happen at equal speeds. Broadband providers allow their users to download at superfast rates, but let them upload only very slowly, creating a bottleneck: If two peers try to swap a compressed copy of Meet the Fokkers - say, 700 megs - the recipient will receive at a speedy 1.5 megs a second, but the sender will be uploading at maybe one-tenth of that rate. Thus, one-to-one swapping online is inherently inefficient. It's fine for MP3s but doesn't work for huge files.
Cohen realized that chopping up a file and handing out the pieces to several uploaders would really speed things up. He sketched out a protocol: To download that copy of Meet the Fokkers, a user's computer sniffs around for others online who have pieces of the movie. Then it downloads a chunk from several of them simultaneously. Many hands make light work, so the file arrives dozens of times faster than normal.
To understand the technology and the extreme genius author Bram Cohen a bit more, read "The BitTorrent Effect" from Wired.