Bitcoin is the film industry's latest weapon against piracy
gizmodo.co.uk
gizmodo.co.uk
I wish the article had more details about how the Bitcoins are embedded - because the obvious question is whether they could be trivially stripped out.
Interesting idea though (which is why I submitted): embed a "reward" in a file, which can be claimed anonymously. But if claimed, you know it's claimed, and you then have cryptographic proof that the file was leaked - and, if you only sent the file to one person, by whom.