I think when new fora are created, one should take into account the content of the posts that are already being posted on the site.
In other words, new fora should filter the kind of content that is currently created on the board.
Since nobody posts about Chicago- or California-specific improv anyway ("nobody" meaning substantially fewer than 50 posts per year) having separate fora for these things seems silly. I have nothing to do with Chicago or California-specific improv, but since there are so few posts about those subjects, I don't mind having them lumped in with NY improv posts.
How, exactly, does the NY improv forum differ from the plain old Improv forum? The difference, if any, is subtle to the point of nonexistence. Instead of reading one forum for NY improv stuff, now I have to read two. This is a time-and-click-waster. And now there are two nearly-vacant fora cluttering up my screen -- the Chicago and LA improv fora.
There just isn't enough traffic in the Improv forum to merit splitting it up into four separate sections.
There is, however, more than enough traffic in the Off-Topic forum to split THAT one up.
Here are some ideas for separate fora that would make more sense:
--Happy Birthday forum (there are lots of Happy Birthday threads)
--Pop Culture forum (there's a lot of discussion of pop culture already -- "favorite tv show" and the like)
--Clueless retard forum ('nuff said)
Seriously, though. The philosophy behind internet messageboard classification should not be "if you build it, he will come" but "he's already here, now figure out whether he should have his own place."