User Rating for Files
 

If there is a file that a lot of people have downloaded, and it is a rotten file, the users who have not downloaded it previously will download it without knowing that it is not what they wanted. The users of Limewire should be able to rate a file, maybe on a scale of 1 to 10, to warn people of bad or corrupted files.

Because there are so many files on Limewire, and they are always changing, it may not be possible to have a permanent rating for some of the files with one host, but if the file has more than one host, you should be able to make it permanant.

Also, you might want to restrict it to people who are sharing or have downloaded the file to avoid people giving there own viruses or ads great ratings.

As for rating files, Bitzi is the way to go, and this is already a part of Limewire. If more people start using it, then it will become even better.

over 2 years ago there was a lot of interest in a study at Cornell called Credence Credence: Thwarting P2P Pollution

For probably some good reason, gnutella developers like LimeWire haven't integrated Credence.

legality most likely