Some people took offense at my comparing Al Gore's "documentary" "An Inconvenient Truth" to Hitler's film "The Triumph of the Will", made in 1934. I didn't say Al Gore was like Hitler, I said the films used similar techniques, namely the are both prime examples of propaganda.
Amazingly, there are unofficial "rule" of etiquette in online, or Internet debates. One of them is called Godwin's Law, and it relates to the use to the words Hitler and Nazi. Apparently this is considered "poor form". However note that there is an exception, and that is when the comparison is valid. See what wikipedia says on the subject.
Godwin's Law (also known as Godwin's Rule of Nazi Analogies) is an adage that Mike Godwin formulated in 1990. The law states:
As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one.
Godwin's Law does not question whether any particular reference or comparison to Hitler or the Nazis might be appropriate, but only asserts that one arising is increasingly probable. It is precisely because such a comparison or reference may sometimes be appropriate, Godwin has argued, that overuse of Nazi and Hitler comparisons should be avoided, because it robs the valid comparisons of their impact.
Although in one of its early forms Godwin's Law referred specifically to Usenet newsgroup discussions, the law is now applied to any threaded online discussion: electronic mailing lists, message boards, chat rooms, and more recently blog comment threads and wiki talk pages.
Godwin has stated that he introduced Godwin's Law as an experiment in memetics.
[There is a tradition in many newsgroups and other Internet discussion forums that once such a comparison is made, the thread is finished and whoever mentioned the Nazis has automatically "lost" whatever debate was in progress. This principle is itself frequently referred to as Godwin's Law.
It is considered poor form to raise arbitrarily such a comparison with the motive of ending the thread. There is a widely recognized codicil that any such ulterior-motive invocation of Godwin's Law will be unsuccessful (this is sometimes referred to as "Quirk's Exception").
Godwin's Law does not apply to discussions directly addressing genocide, propaganda, or other mainstays of the Nazi regime. Instead, it applies to inappropriate, inordinate, or hyperbolic comparisons of other situations (or one's opponent) with Hitler or Nazis. However, Godwin's Law can itself also be abused, as a distraction or diversion, that fallaciously miscasts an opponent's argument as hyperbole, especially if the comparisons made by the argument are actually appropriate.