A chat room is a private conversation inside a newsletter's community, open to one slice of its audience. The people in a room see it in their chat, with its name on it, and only they can read what is said there.
A room is a tag. The same row appears under Subscriber tags with
is_room: true, and the two readings are both true: a tag is a slice of
the audience and a room is a place people talk. Which is why these
operations need audience: read rather than content, and why tag on
a Room is the same id the thread audience writes accept.
Read only. Making a room, hiding one and removing one are done in Commune: each of them is the creator agreeing to publish a name they wrote for themselves, or withdrawing a conversation other people are in.