Like the other pissy-stared moderator said, personal attacks, degrading statements made toward or about a person because of his or her likes, beliefs, interests, etc.
Example: "95BonnevilleSESC is a stupid retard because he likes Lincolns"
Example: "Willwren is a fat toehead"
Example: "BC members are (insert appropriate expression here) because Bonnevilles are slow grocery getters and everyone knows that (insert appropriate rice car here) can beat them.
These are lame examples, but you see the pattern of personal attacks in the first two, and the general purpose of flaming for the sake of rable rousing in the third.