Because of the trust that's formed the last decade, we've had meetups all over the world. No matter what country you're in — there's usually a rooter who's got an open door. In addition, TR42 isn't just about art... it's a living community and people share very personal details that they don't want index by spiders or viewable by the general public. I'm not going into specifics but it gets very personal.
Don't think my account is still there though... ;-)
My point being is relying on UX patterns and human factors theory does not negate the most important UX principal and that is A/B testing. Users may not be able to vocalize what they want but their actions and conversion rates speak volumes about what is intuitive and what is not. Employing this simple technique can teach you volumes about intuitive interface design.
Now with that being said these communities are great for inspiration and as a support network when creativity or ideas fade. When you hit a creative block they provide a plethora of talented people that can be extremely helpful.
Just remember, if you A/B test something and it goes against conventional wisdom, stick with what works avoid the dogma. Always do what works, not what is supposed to work.
While Pick.Im isn't exactly a community, it's a pretty fine resource for getting your name out there (or finding developers); I just used it the past week to find a bunch of great local (Denver) UI designers that I'm interviewing.
I'd also look at Product Management groups as UX is a specialism within that, so ProductCamp and ProductTank for starters.
