Well, discussion threads would actually go in the Writer's Lounge subforum. So if you post there, then you'll be fine. That rule's just so that's there's no instances like what you said, where everyone posts in one thread.
So, I wanted to post a thread in the Poetry section but I had a question.
No threads purely on one type of poem.
My idea wasn't to have a thread where people posted their own poems, but where people discussed slam poetry, whether they often went to poetry slams, etc. But that's technically one kind of poetry, so...? Thought I'd ask before I accidentally broke a rule :x