I launched Local SEO Community about 3 months ago, and just crossed the 850 member mark.
Local SEO Community is a community for discussing Google My Business and local SEO (as opposed to SEO as a whole) tips and strategies.
Pretty happy with the level of engagement in the community at this point. Whenever someone posts something, there are normally a couple of responses within a few minutes.
Hoping to cross 1,000 by the end of November 😀