BitTorrent finds another legal use: Facebook's server farms
You wouldn't have thought it troublesome -- source code is fairly lightweight after all -- but when you consider that Facebook has tens of thousands of servers... well, you can begin to imagine the logistical nightmare of rolling out code changes on a regular basis. With BitTorrent, it takes a matter of minutes to update every single Facebook Web server with new software -- awesome!
As TorrentFreak points out, Facebook isn't the only large company that uses BitTorrent -- so does Twitter! BitTorrent isn't relegated to internal uses, though: Blizzard uses it to distribute huge patches to its 12 million World of Warcraft subscribers!
You only need to take a quick look at the BitTorrent Inc. Wiki page to get a better idea of just how many companies might be using BitTorrent to speed up their data transfers.