An inside joke among Bellsouth Dial-Up tech support agents (actually Calltech, who outsource for Bellsouth). Comes from a phony customer listing named "Monkey Butter" which was used much like a message board between the agents. It had a lot of funny posts and lots of HTML. It was eventually deleted when one of the supervisors caught wind of it.
On a related note, another agent created a listing called "Son of Monkey Butter" and was fired in short order for it.
"Dude, check out what somebody put on Monkeybutter!"