Behold an exception to my rule: AboveTopSecret.com is a website that deals with...alternative topics. Aka, conspiracy theories.
And their little disclaimer at the top not only declares that they are the most popular of such sites on the Internet (which may well be true; they're certainly large and frequented), but also that they are "intelligent" and "civil."
A quick check of the forums shows posts that are neither. But they're SO far off the board that I had fun laughing at them; if I could've posted without registering, I would've turned into a polite little troll. :)