The first that come to mind are Niggermania and Chimpout.
Niggermania was started in the 90s, and it was the project of one guy who wanted to document everything wrong with niggers. Eventually it absorbed other smaller sites, and a forum was created. They created terms like "chimpout" and "coalburner" which have now become somewhat mainstream on the Internet, and also made hundreds of memes about everything from bix nood to lootie and jenkem (an African drug made with fermented human shit). Eventually there was a split and Chimpout was created as a rival forum. Chimpout was generally younger and less Southern/Confederate, and they even made a "radio station" that played racist podcasts.
On both sites, you could only a-log niggers and, after 9/11, Muslims. If you made a comment about any other race or religion you got banned. Often this resulted in some funny rants about how much better they were than those fucking NAZI WHITE SUPREMACIST SKINHEADS who didn't like Jews or Mexicans.
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