A term originally used by the Ottawa XVI community meaning posing as someone else and posting to a forum in their name when they leave their computer and account logged in or when they use auto-fill for passwords in their browser.
Believed to have been originally coined by someone posting "I am a poohead" on the initial victim's account and has since been known as pooheading or being pooheaded.
(Note, logging in as someone when you know their password and posing as them is NOT considered pooheading. To qualify, the victim must have left his/her account logged in; the alternative is just considered a misuse of password knowledge privileges.)
" - Did you read Graham's post? He sold his car to fund becoming a roady for 98 Degrees!
- I'm pretty sure that was just a poohead."