Programmer Bram Cohen began designing the peer-to-peer (P2P) BitTorrent protocol in April 2001. On July 2, 2001, he posted the following Yahoo Groups message: "My new app, BitTorrent, is now in working order, check it out here -" Today, the protocol is thus 10 years old.

Cohen wrote the first BitTorrent client implementation in Python. The initial response for the new P2P protocol was next to nonexistent. The only reply he received on the message board read as follows: "What's BitTorrent, Bram?..."

In the summer of 2002, Cohen collected free pornography to lure beta testers to use the program. BitTorrent became popular thanks to its ability to quickly share large music and movie files online. Although Cohen never supported piracy, BitTorrent would never have become popular without it.

Today, BitTorrent is one of the most common protocols for transferring large files. In November 2004, it was estimated that BitTorrent accounted for 35 percent of all Internet traffic. The latest data, from February 2009, puts the number anywhere from 27 percent to 55 percent of all Internet traffic (depending on geographical location).

The protocol is now maintained by Cohen's company, which also goes by the name of BitTorrent. There are numerous BitTorrent clients available for multiple computing platforms, the most popular of which is µTorrent. Version 3.0, which adds many new features, was released just last week.

In January 2011, the company revealed that BitTorrent and µTorrent hit 100 million monthly users. On an average day, 20 million users from over 220 countries use either of the two BitTorrent clients, available in 52 languages, and 400,000 new clients are downloaded every day.