@PaulBender is there any specific setting that needs to be changed in order for this to work? By default I can't see any "Thread Count" on the forums. It would be good if you could explain that (otherwise other people, especially those that update the docs) won't know about this.
The only setting that exists is a forum option that allows you to disable threads in that forum from being counted. Otherwise, thread count should always appear in you profile, postbit and member list.