One more INTP here. I think these tests have some validity although I wouldn't be foolish enough to make hiring decisions based on them. I took the real MB in college with a class of about 30. After we got the results we spent some time guessing what other people in the class would be and just discussing the results. It was interesting and most people felt the results where pretty accurate.

Even if they aren't perfect knowing the different personality types MB defines gives you some advantage in dealing with others. I was a resident assistant for a couple of years which kind of forces you to be outgoing. Being able to categorize somebody and use some of the MB guidelines for how to interact with them can make that easier for us introverts.

Anyway, interesting stuff as long as you don't take it too seriously.

-Mike