I have an idea about automatically locking posts which have not had a reply for a certain number of days (maybe 60 or 90, could depend on which room it's in).
I think it would be fairly easy to write a script to do this.
It would prevent people dragging these old posts back to the top of the pile, but they would still be there for reference, and the mods could still unlock them if they suddenly became relevant again.
Didn't think so.
Ok mods, you can close this one already.