It might be worth considering what answers you give now that might be different than ones you gave 7 years ago. I know I took one of these back in college, and probably every 5 years or so I've revisited it, each time never recalling my previous result (what does THAT say about my personality?). 

But it struck me this time that some answers I gave this time would have been different 5 years ago. Enough that I probably would have been rated a different alphabet. 

For the record: ENFP   (slight, distinct, moderate, slight).

Like the sun over course of the day, our luminousity and spectrum change over time, from the blue tints of dawn to the harsh light of day, and again the blues towards dusk if I recall correctly, followed by gruesome darkness. 

Anyway forgive my lyricism, but you catch my drift (although some claim that people never 'fundamentally' change, I disagree).

I wonder if there's a way to measure how an individual is trending over the years, probably by comparing a series of tests over the years (although I think the act of taking thr tests repeatedly would tend to increase introspection, in the manner of observation effecting the outcome).

I think it depends on what the test is actually measuring - and the phrase 'personality type' doesn't seem to be descriptive enough to be useful in determining that.

If my earlier 10-second assessment turns out to be right, and the test is measuring which types of bias people are most prone to, then a high overlap in 'personality types' could be an indication that the people here tend to have significant shared blind spots and thus a lower-than-ideal chance of noticing them in each other. If it's measuring something that's not relevant to rationality, I don't think the overlap matters, but I'd also be somewhat surprised to see a high overlap in test results in that case: I don't predict that the people here have a high level of similarity in results on the love style test, because affection-awareness isn't something that's relevant here in any way that I can see, but people who are interested in rationality but prone to different biases, and less prone to the (hypothetical) set that we share, would probably not stick around in a place that has flaws that are obvious to them, so selection bias seems relevant in that case, and would have the observed result.

Of course, it could also be that 'personality type' somehow results in more or less interest in rationality, rather than being caused by something that's relevant to rationality. Figuring out what the test is actually measuring should hopefully clear that up. (I suspect that the kind of selection bias that I mentioned does happen, though, even if it's not related to the MB test - I follow the blogs of several people online who are interested in rationality in completely different ways than we are here, and who I predict would feel quite unwelcome here for reasons that are only tangentially related to actual quality of thought.)