I thought that too, until i bought a cheap netbook that came with windows (7? Student edition? I cannot remember). I plugged in a mouse and windows said it needed to connect to the internet to download the driver for my MS optical mouse. I practically fell out of my chair laughing.
Except the mouse wouldnt work. Either the os couldnt use it, or wasnt letting me. Either way, it was funny seeing one ms product not recognize another.