Consider myself as member of two gaming communities (this is one of them). In both I've met exactly two INTJs, first having formal education and second without it. In this community, second would be you, dear Xant. First type is, of course, Kafein. Funny thing is, I tend to get along with INTJs despite being daft as a board. Although INTJs are very interesting crowd, I prefer those calm types hard to provoke. My greatest accomplishment in cRPG always will be when I pissed off Logen.
INTJs aren't easy to spot as link suggested but thats not the case with intellegent people. They are so easy to spot, just look them in the eyes.