TBH, I really like Facebook's groups in terms of UX and maintainer level. I don't like FB themselves though, and their warnings are sometimes just at a level of insane.

Keep thinking I'd like to create an easy button for FB groups like self-hosted community setups. Then you can control/host your own interest group... add in live group chats (that FB used to have for groups) and just have a centralized auth and search that are opt-in.