Sometimes they will just drift slowly down the charts, until they are forgotten by everyone.
Everyone except the search engine.
I easily spend 10x more time searching OFPEC than posting. Alot of the old threads that only have a few posts are VERY helpful for someone new to OFP/ArmA scripting.
Having been admin at different forums in the past, I know it is a balance in terms of how many subforums and what kind. I think OFPEC's structure is very effective - and the aforementioned search engine is top notch.