It means you're either a) using the same computer; b) all in a computer lab or on some sort of shared net connection; or c) have multiple accounts, for which you can (and probably will) be banned.
"I'm a dog chasing cars. I wouldn't know what to do if I caught one. I just *do* things. I'm a wrench in the gears. I *hate* plans." - The Joker http://pressthenyckbutton.blogspot.com/