You can share your desktop's DVD drive over a network like you would share a folder or hard drive. Also, I guess theoretically you could use VPN (Virtual Private Network) to connect to your home network and use that DVD drive (or hard drive if you don't mind really slow transfer speeds) if your on the go, which would be useful if the game requires the disk to play, but it's really just simpler to use a USB drive. Also, you can plug a full size desktop keyboard, mouse and monitor into them. Oh yeah, World of Warcraft will run on a toaster.
i have 2.5 gigabytes of ram and it only uses 37%. Out of all the newer PC games i own this is the least memory heavy game since most games use around 70%.
_Margulis_'s comments