What I hoped to gain requires an essay-length answer. I will do that for a writing class and do a summary here. In one word, non-work-related conversation.

Mensa is simply a social club like any other. Once you're in, you join various Special Interest Groups, and network with other people based on shared interests.

Just the M-Atheist-Alt discussion forum can hit 1,000+ messages a day. The GenX-Ms email forum used to be as large, until the bulk of members flipped to Facebook. Every SIG sets up it's own forums.

Self esteem... XP I qualify but am so not interested in it.

All of the money and degrees in the world and you will never match up to a Mensa membership.

I found out that a friend of mine was also a member. We went together to an air show which was loud. Later after moving across the continent, I went to one meeting and then dropped out. In other words, I didn't get much out of it. Maybe it helped me get into grad school to have it on my resume?

@mudhen -- What one gains by joining Mensa or any other group will depend on the expectations of the one doing the joining. I was a member for a couple of years and enjoyed the various SIGs that were aligned with my interests. I dropped it because my work kept me from participating enough to justify the dues, but I have no complaints. Later, I contemplated the Triple 9, but never acted on it. So, if you're thinking of joining, there is only one way to answer your question. Join. Then decide your next move.

I would think other bright people?

I've never done it - found out that I had scores to enter. Realized they'd take me and wasn't so interested? lol