Now that online play in New Leaf is gone, will the sub-forums related to it be permanently closed? I bet it will be, look at what happened to The Auction House and The Gate in the City Folk sub-forum.
We have not discussed this yet, but I think it's likely. Oblivia stated in an earlier post that the New Leaf board will probably get moved into the General AC forum after the servers shut down and I imagine the NL specific trading boards would be closed at the same time. For the older games that no longer have Nintendo online support, there isn't as much activity so it's common to make threads in the main board for visiting or trading.