One who's actions (deliberate or otherwise) seem to attract the hatred of the rest of the forum; see flame. These people do not seem to learn from their actions and are delt with by issuing a sympathy ban.
These people can be grouped in sevral diffrent catagories ranging from beer weed to trolls.
"He never learns, he is getting flamed right and left."
One who's age matches their IQ. They often have a "420" somewhere in their user name. A person who joins an Internet message bored to do nothing but asks stupid inane questions. This person is regarded as flame bait.