Well, my tentative conclusions are as follows.
According to random stats, Infj's and Intj's, put together, comprise only about 4% of the US population. Yet, in this totally unscientific survey of the Mane, they make up almost 50% of those responding. (7 out of 15)
In another board I'm on, those two groups make up 90%.
I suspect that those two categories of people tend to be drawn more toward message boards than the other groups, for a variety of reasons.