[drewmeyers24]

Building "a community" is one thing. You don't need a product to build one community. You really just need passion, credibility, and perseverance -- and some combination of a blog, email list, and facebook/slack group as the tool.

Building a bunch of communities (aka facilitating community) is a different beast entirely, and seldom takes off very quickly at all. The best example of facilitating community is Meetup.com.

I've been working on a facilitation of community model called Horizon (http://www.horizonapp.co) which is best thought of as airbnb/couchsurfing with friends, friends of friends, and communities. So, privately, rather than publicly with strangers.

You can either facilitate existing community, or build a community. Trying to do both is a recipe for disaster imho.