The general impression that I get is that smart and effective people are too busy doing awesome things to join Mensa. If I wanted to recruit rationalists I think I would do better by looking for effective people and picking the smartest ones instead of looking for smart people and picking the most effective ones, especially if the process I'm using to look for smart people actively puts selection pressure against effectiveness. (CFAR running workshops directed at entrepreneurs seems to be a strategy in this vein.)
I also know a few smart and successful people in Mensa. However, they were all successful before joining Mensa, and as far as I know Mensa did not help them become stronger. Their "being successful" and "being in Mensa" are just two traits that randomly happened to the same person; there is no synergy. They are successful during their time outside Mensa, and they come to Mensa only to relax.
(As far as I know the only way to use Mensa to become more successful is this: Do something that you would be doing outside of Mensa anyway, but con...
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