Yes but beeing on line isn't the same as posting. My girfrend can make me look online just using my computers chrome. I don't see forum as hi security so I'm logged on all the time. So that only means that someone used Slush computer.

EDIT: or it might even be just logged on his account with forum open if he is online all the time or someone wake computer up from sleep or hibernation if he is not on all the time.