Exactly how new boards will affect rules for the main board is an area of uncertainty. A permanent shitposting board is probably going to result in a de facto banning of shitposting from the main board, with shitposting threads being moved. Perhaps some threads will be allowed on the main board. mlpol.net has not historically had an enforcement of board topics, but may soon.
I think it should be a bit more relaxed than that, with maybe a couple of funposting threads on the main board, but I certainly approve of the bulk of them being moved.