[MaximumYComb]

I think you're only looking at "smart people" as people who want to share how smart they are. You seem to be ignoring the social isolation that can come with it. Your interests might no be similar to those around you, if you're a child you might be able to meet others who are different in the same way, etc.

I very rarely discuss IQ since so many people are hostile to it. A high IQ makes you different. Sometimes it's subtle, like as an adult you'll typically have different interests compared to a lot of peers, and other times it's far less subtle, like when you're a school aged kid and you're always made to feel different (FYI most school aged kids don't want to feel different).

[allenu]

I suppose so. It's probably more akin to a club for tall people, or a club for twins. There are things specific to who you are in those cases that outsiders wouldn't "get" and I can see the value in meeting up with those folks to feel a sense of belonging.