Unleashing the Monster Download Using file sharing for good instead of evil, BitTorrent is helping companies save a bundle.
By Matthew Maier

(Business 2.0) – Blizzard Entertainment knew what it was in for when it announced in March that fans of its Warcraft computer games could download an online role-playing version for testing: 100,000 would-be orc killers sweeping down on its website to grab the mammoth 2-gigabyte download. In the past a traffic spike of that magnitude would have bottlenecked or even crashed the Irvine, Calif., game developer's servers, and infuriated gamers would scream with blood lust.

This time there was nary a whimper. That's because the company tamed the bandwidth-hogging hordes with an ingenious file-sharing system called BitTorrent. Though "file sharing" carries a shady connotation for those who think of it in terms of illegal music downloads, this open-source software is not just free but also legal.

Simple too. Normally, when you attempt to download a file, your PC waits in line with all the others trying to get it. Once you install the program, BitTorrent breaks the file up into pieces and instructs the host server to send these bits to all the waiting PCs, which then share what they've received with other PCs asking for the same file. By reducing both the number of servers and the amount of bandwidth needed--20,000 users have downloaded a file simultaneously, something that would bring most servers to their knees--BitTorrent can cut infrastructure costs by as much as 50 percent. "BitTorrent is the most efficient distribution scheme we've seen," says Blizzard producer Mark Kern.

Despite its cost-cutting potential, BitTorrent initially got the cold shoulder from the corporate world. Bram Cohen, a 25-year-old unemployed programmer when he created the system in 2001, posted it on the Web and encouraged others to adapt it to suit their needs. BitTorrent has since been downloaded more than 13 million times, according to SourceForge, a website that hosts open-source projects. Early adopters include software developer Lindows, which uses BitTorrent to help distribute its version of Linux.

As for Cohen, he's cool with the improvements that have been made to his brainchild, as well as its growing popularity in corporate America: "It doesn't suck anymore, so I'm happy to see people picking it up." -- MATTHEW MAIER