I'm aware that there is a red file symbol for an active thread. I would throw out a suggestion to the moderators to section off a "most active thread or post list" which would help in directing all community members to the present days most active discussion from the entire community site !
I may be mistaken, but I think the red folder just designates threads with 10 or more replies, even if those replies are pretty old. So maybe some sort of new designation is in order for most active threads -- a separate section, like you suggested.
-e-....you and I had this discussion earlier this month....perhaps "expiration" or "archives" are in order with the upcoming modification of the community....the expansion of the numbers of new members will eventually require better organization