Building a community is like pushing a car uphill. It’s a lot of effort. Gradually you build momentum and the hill gets less steep. Then you get to a point where the car starts to roll away from you, and you walk away happy*
Managing a community is keeping that car on the road as it speeds away. You have to make sure it doesn’t crash, run out of fuel or neglect it’s maintenance.
to put it more literally: Building is about creating the right structure, cajoling the right people and creating an autonomous group that can thrive without you. Managing is about keeping the group together, keeping clear communications between client/community and ensuring the community doesn’t collapse.