I just had an idea that I for one would love to see. It would be similar to the "related tribes" function in a tribe, but this would be for an individual. The logic would be: take all the tribes a person belongs to, find all the people in those tribes, find all the tribes those people are in. Then, rank by frequency, trim out any tribes the original person is already in, and report the top 10-20 of the result. (Or perhaps it could have a "more" button and you could see more than the top 10-20)

Let it be a module that one could add to one's homepage.