Would you like me to move this into features? 
We’re using the category level a lot so that we can run support for a number of different language courses on one instance - it seemed like a very neat solution for us, so I can certainly imagine other sites with wide ranging userbases doing something similar.
Lovely work, by the way. We were banging our heads against the wall trying to roll our own, we were so desperate to escape from the legacy systems - very pleased to see how many of the things we really wanted have been baked into Discourse 