Magnet Links is a proposal for being able to link to files on any P2P network. I remember back in the day I listed my mp3 collection on my website and build napster: URIs to link to. This seems like a useful tool, because it’s an open specification any P2P tool can implement it.
One thing to remember is that you should triple check that anything you link to isn’t infringing on anyone’s copyright. Why? Because linking to infringing material "might be a contributory infringement of the work’s copyright." Sort of like if you tell someone where a crack house is you’re guilty of selling crack, or at least you would be if all laws used the logic of the Digital Millennium Copyright Act. I am not a lawyer though, so the preceding paragraph may be bunk.
Remember kids, only MagnetLink to stuff in the public domain or licensed with a Creative Commons license. Wow, only 2 days old and MagnetLink is already a verb. Still, it won’t necessarily catch on, it’s not like feed:// URIs are useful yet.