I didn't know you are already working on the next feature for communities, awesome! One thing: I don't know if you saw the discussion about making configurable options for communities instead of having different types of communities. Making it configurable will allow communities to switch as they wish between being closed to new members and being open. So you don't have to start a new community if you want to make such a change, it's just a settings change. Many communities might start out very open, but over time as they get more members they will likely experience more spam or irrelevant posts so they may decide to make posting more restricted (instead of starting a new community). Would it be difficult to implement this kind of community configuration?