There's a few aspects of successful communities that I've seen. First, there is a clear articulation of a problem/challenge that people can quickly identify wi

There's a few aspects of successful communities that I've seen. First, there is a clear articulation of a problem/challenge that people can quickly identify with. Second, there is a urgency of action that draws people in, that if this problem is solved the world will be a better place. Third, there is an approach articulated that addresses the problem and has a reasonable chance of success. Fourth, there's room for engagement, and engagement has two parts: there must be enough structure so that a participant isn't overwhelmed and has a path they can follow; however, this path must afford quite a bit of creativity and freedom so that people can have a meaningful engagement on their own terms. Finally, and this might be obvious -- the community culture has to be fun and welcoming.