What is a small community? Could be many things.
In my mind I always think of the group chat with rules and visibility enforced by a temporarily trusted relay (the NIP-29 approach); or having one or more restricted relays be used for different purposes in a microblogging client that surfaces these purposes and these relays to the user (the Pyramid + Hallway approach); or it could be simply relays-as-groups with an interface that focuses on one single relay (the Flotilla approach).