In a paper presented at the Usenix Workshop on Large-Scale Exploits and Emergent Threats researchers devised a way to monitor BitTorrent users. By monitoring the users they accomplished to create a list of ip-addresses of individuals and track the content they are sending and receiving.
In that paper the researchers demonstrated the technique to continuously spy on BitTorrent users for 103 days. They collected 148 million IP addresses and identified 2 billion copies of downloads, many of them copyrighted.
From this research most important is that identified the IP addresses where much of the content originated. This means that the individuals that creating the torrent files are few. Therefore, the question is why the anti-piracy groups try to stop millions of downloaders instead of a few content providers.
