But his open-source software, now one of the most widely used means of legally and illegally downloading files such as movies or software, has barely helped him earn a living.
Now the programmer is aiming to turn his donation-supported work into a steadier business, with a San Francisco-area start-up devoted to BitTorrent products. The first product, to be released in the next few days, will be an advertising-supported search engine that scours the Web for links to BitTorrent files.
"We're trying to make it a less haphazard revenue stream," said Cohen, who is moving back to the San Francisco area for the project.
The search tool, which will be based on Web crawling technology owned by Cohen's company, could be a boon to downloaders who previously have had little in the way of navigation for BitTorrent files.
Unlike peer-to-peer networks such as Kazaa, eDonkey or the original Napster, no central search technology exists for BitTorrent. Instead, links to specific files are posted on Web sites. Sites that specialize in copyrighted files such as movies or music are often taken offline by legal action.
A few tools have existed to get around this process. Exeem, an application distributed by the former operators of SuprNova, a big BitTorrent Web site, integrates Cohen's downloading technology with a more traditional searchable file-swapping network.
An older Web search tool called Bitoogle also has provided some search capabilities. Cohen said his BitTorrent search will be more powerful than Bitoogle, however.
Cohen said his tool won't aim to screen out the myriad copyrighted files likely to come up in a Web search. But like other search engines, he will comply with federal copyright law and remove any links that copyright holders point to as leading to infringing material.
Plans for the new search tool were first reported by Wired News.
Cohen said his new company, eponymously named BitTorrent, will also host file downloads in torrent form and consult with companies wanting to use the technology to distribute their own products.
