Magnet links just automatically open your torrent handler, so there is no need to download the .torrent file.
How would that help stop torrent sites from being shut down?
Yes, I know it looks and does the same thing, but Magnet links are so far removed from Trackers, it's insane.
A Tracker is a web service that keeps a running list of IP addresses per torrent. Your BT client connects to trackers to download lists of seeds and peers, then connects to those IPs to start downloading.
A Magnet URI isn't actually a URI at all. The data in a Magnet link is a description of the content, not the location. A Magnet client will connect to the Gnutella network, and spider out through local leaves and nodes, searching each one in turn for content that matches the hash in a Magnet link.
The major difference? It's
completely decentralized. In order to stop a Magnet sharing scheme, you literally have to shut down absolutely every single computer that's serving or downloading stuff over Gnutella. And short of blowing up the planet or suing every single ISP in existence, that's just not happening.
The other issue is that, for instance, TPB no longer hosts a tracker. All they host now is a massive database of Magnet links. That tracker was a major weapon in the litigation arsenal, since they maintained a web service that
actively assisted in copyright infringement. Now that it's gone, they'll have to try to sue TPB for hosting plain, inactive links, and that'll be monumentally more difficult.
Edit: Forgot to add - premier example of Gnutella P2P:
http://www.limewire.com/ . LimeWire goes even further, though, routing your searches through Gnutella itself. There aren't any servers, sites, databases or trackers, just 70 million clients in a decentralized network.
