"Leaving" LW is rather strong. Would that mean not posting? Not reading the posts, or the comments? Or just reading at a low enough frequency that you decouple your sense of identity from LW?

I've been trying to decide how best to pump new life into The Octagon section of the webcomic collective forum Koala Wallop. The Octagon started off when Dresden Codak was there, and became the place for intellectual discussion and debate. The density of math and computer theoretic enthusiasts is an order of magnitude lower than here or the other places you mentioned, and those who know such stuff well are LW lurkers or posters too. There was an overkill of politics on The Octagon, the levels of expertise on subjects are all over the spectrum, and it's been slowing down for a while, but I think a good push will revive it. The main thing is that it lives inside of a larger forum, which is a silly, fun sort of community. The subforum simply has a life of it's own.

Not that I claim any ownership over it, but:

I'm going to try to more clearly brand it as "A friendly place to analytically discuss fantastic, strange or bizarre ideas."