File sharing isn't just for kids. P2P networks, typically private, are increasingly integrated into the business world. The Wall Street Journal featured a few different examples.

Vehicle manufacturer GM uses P2P to deliver daily internal video to car dealers and sales staff in latin america. Coke used P2P to distribute large videos among business units or to all its employees. Kontiki, now part of Verisign, was the supplier for GM and Coke.

A popular and low cost corporate P2P alternative is Bit Torrent-based software, provided by Bit Torrent itself, my own company RazorPop, and many other developers.