Forum Archives
Background: The original SpongeBob Community was formed out of a group of disgrunted users of the SpongeBob SquarePants forum.
Since deleted all of its forums in 2016, you can find the SpongeBob forum as well as other forums preserved in their entirety below:

SpongeBob SquarePants
Avatar: The Last Airbender
Avatar: The Legend of Korra
Total Drama Island
The Penguins of Madagascar