Something about the forum communities is that you couldn't isolate yourself from people that disagreed with you. On facebook you can limit who you interact with, so if your ego or your beliefs are challenged you can remove that person from any future discussions. In the forum communities this was impossible unless you were an administrator. Once you became an admin you were then under the microscope from the rest of the community to operate in a fair way, though this didn't stop some admin's from completely destroying their communities or turning the community into an echo chamber.