This relates to an idea I had: create a "fair use" file sharing network, by posting carefully-chosen 10 to 30 second "review" clips of songs on various web sites, then distribute a tool (script, program, whatever) that can locate the pieces and reassemble them.
For that to work what you would need is an annotation protocol reviewers would adhere to (hash, start-end) that could allow a downloader to locate the missing pieces. The locator tool would also have to be designed in such a way not to ruin the fair-use defense too.
This is not a trivial problem and, I must add, we are talking about a tool designed to violate copyright laws and to get away with it.
It would be much wiser to direct our efforts towards a more rational copyright system instead of trying to break the law.
And we all know public opinion is never wrong.
It's really easy to share copyrighted files. It's easier, in fact, than downloading them. Both are so easy people overconsume. They download more music than they will ever hear - music they would never buy if they had to incur the cost.
More interestingly, how do plaintifs prove the sharer allowed the copy of the whole file? It's easy to imagine any downloader got the files from a number of different sources, each effectively sharing a tiny part of the file.
Thinking about it... Couldn't the protocols not advertise the parts of the file the sharer has, but, instead, receive a list of wanted parts from the downloader and respond with some, but perhaps not every, part of the file? What would happen to these lawsuits if nobody ever shared the whole file with anyone?