The BitTorrent peer-to-peer (P2P) file sharing protocol was estimated by internet traffic management and analysis company ipoque to account for roughly 27 to 55 percent of all internet traffic as of February 2009 – much of it pirated software, music and video files. While the distributed nature of P2P networks sees millions of users sharing files every day, a new study to examine the behavior of users responsible for publishing files on the Mininova and The Pirate Bay portals reveals that a small group of around 100 users is responsible for the majority of content published over BitTorrent.

The Carlos III University of Madrid (UC3M) study examined the behavior of users responsible for publishing over 55,000 files on Mininova and The Pirate Bay in an effort to understand what they got out of it. Since such users dedicate a large part of their own resources in terms of bandwidth and storage capacity and assume risks involved with publishing content protected by copyright laws the researches wanted to discover whether it was purely altruistic behavior or whether there was some economic incentive at work.

The researchers’ analysis demonstrated that a small group of around 100 users were responsible for 66 percent of the content published and 75 percent of the downloads using BitTorrent applications. The UC3M researchers, working in collaboration with scientists at the IMDEA Networks Institute, the University of Oregon and the Technical University of Darmstadt, identified who these users are and what their incentives for massively publishing contents are.

There were basically two different profiles that the publishers fell into. The first is so-called “fake publishers”, which includes organizations publishing large quantities of false files as a way to protect their copyrighted material, and malicious users looking to spread infected software. The second group includes a small number of users known as “top publishers” who massively publish content on BitTorrent to make a profit from online advertising and, to a lesser degree, from VIP subscribers who wish to speed up their downloads.

With such a relatively small group responsible for the bulk of illegal content the study’s authors predict that if these users were to lose interest due to a loss of advertising revenue or be eliminated from the system through legal action, “BitTorrent’s traffic will be drastically reduced” because so much of BitTorrent's success is centered around the availability of popular content, such as new release films and television shows, which is typically pirated.

But tracking down members of this small group of users could prove difficult. To carry out the research, the scientists developed a tool that allowed them to access the name of the user who published the content, his/her IP address and the IP addresses of those users who later used the BitTorrent application to download the content. However, they found many of these users publish content from servers rented from companies that allow the users to remain anonymous.

The study, titled "Is Content Publishing in BitTorrent Altruistic or Profit Driven?", was recently presented at the ACM International Conference on emerging Networking Experiments and Technologies (CoNEXT).