Pirate Bay working on a mysterious new site
pcmag.com
pcmag.com
The only thing I can think of is a P2P network, where every user of the protocol becomes a node in a TOR like network, but then you will be dealing with horrible bandwidth issues. My 7MBit DSL only has 1MBit upstream, which is hardly enough for me to route more than 4 other user's traffic through. That still doesn't solve the issue of privacy and anonymizing the users, since a user of the program, even if he is not actively downloading and uploading a file that he requested, is still liable for distributing a portion of the copyrighted files other users are requesting and distributing. You may not get the end point, but you'll end up with a whole bucketload of people facilitating the infringement.
I'm not an expert in flash and not sure if a flash app would allow a remote connection to a server other than the one where the flash app is hosted. I think some XML file is required on the other server that flash will look for to see if theres a wildcard to allow any domain to connect... I saw an exploit once for twitter or facebook that used this. I am quite positive this could be done with java though.
Basically a torrent client in java/flash that downloads mp3's only. Because mp3 files are fairly small the downloaders not becoming seeders shouldn't be much of a problem (so long as desktop torrent clients grow as the music site grows, which I think it will).
EDIT: I think this is a fairly good and obvious tactic to create the next big thing. Basically take a desktop app and find a way to put it on a website. Eliminating the need to download an app (torrent client in this case) can dramatically increase popularity.