[@robkk Moderator 11 years, 2 months ago]

Yeah bbPress Moderation is what you are looking for although it seems to be unmaintained. Only thing I can say about this is to make sure you have the plugin set up properly, to make sure it works well.

There is a bbPress role of Spectator which the user cannot post and only view forums. You can later switch them to Participant later in the Users section in the WordPress backend.