Engadget has a terrific interview with Michael Robertson - computer iconoclast and founder of MP3.com and Lindows/Linspire. Robertson's latest venture is SIPphone, a player in the burgeoning VOIP market. The interview covers a lot of ground including this tidbit about SIPphone competitor (and recent eBay acquisition) Skype that I did not know:

"One of the things Skype does, which I think is petty sneaky, is to use your computer to route other people's telephone calls. They could be using your processor and your bandwidth as a supernode to move other people's calls, and that's something that we don't do. We have servers and data centers around the world that relay calls, and we never use your computer for other than your own call. So I think this has made Skype fairly unpopular with enterprises that guard their network resources, and some users have noticed real slowdowns because their computer moves calls for other people. You can't turn it off, too."