Godwin's Law

For those unfamiliar with Godwin's Law, it states that the probability that Hitler will be mentioned in a discussion thread approaches 1 as the thread gets longer and longer. Why Hitler? Because Hitler has now become a generic insult for anyone you don't like. Godwin himself set out to point out how silly it is to just call people Hitler all the time (because it effectively ends all rational discussion), and that's how it all got started.

This thread, for example, was doomed from the start.