There are thousands of good reasons to work with communities (be it audience development, employee happiness, customer retention, organization design, education, brand extension — you get the gist), but it should be in support of strategic goals, such as higher customer retention, better internal collaboration, external thought-leadership, lower employee turnover, etc. The community is not a goal in of itself.
The Community Logic Tree — Medium
quote pulled from essay on Community Design Thinking or the design of communities for commerce (my interpretation)