I've poked around INTJf a couple of times. There was a lot of good information on the subjects I was researching at the time, so I don't really have any complaints. On a more subjective tip, I feel fairly at home with the INTJ communication style. It's no frills and blunt, but speaking as an NTJ there's something enormously comforting about being able to speak without having to accomadate others stylistically. Think of it as being in a foreign country for years and years. While you may be fluent in that second language, there's nothing like stumbling across a bar frequented by fellow expats and being able to hear your native language spoken, and being able to act in a way natural to you without having to second guess yourself. It's a relief.
I guess my point is that if you go to a forum like that and don't get it, it's probably not for you.