Also from Kuro5hin:

“Godwin’s Law: As a Usenet discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one.

popularly understood as “the first person in an argument to refer to Hitler or the Nazis loses the argument”, but it isn’t a law like “murder is a crime” is a law. It’s more like Newton’s Laws–not something that can be “invoked” or “violated”, but an observation of the surrounding world.

Godwin’s corollary: When someone takes an unofficial “law” like Godwin’s or Moore’s too seriously and writes new corollaries for it, they automatically lose.

*ponders…*

I concede defeat! :o”