It was helpful when the Requests for Donations/Donations (PIF) was separated from the For Sale and ISO in the "old classifieds"
I think it will be easier to use the subcategories now - the challenge is to get people to read the rules, and post things in the most appropriate place.
An example of an ambiguous post:
In Main - "I'm looking for xyz fabric" - Is the poster just wanting to get suggestions of where to buy xyz fabric from a commercial source - or is she asking members if they have any available to beg, buy, or barter to get
If the poster is ONLY interested in commercial sources, I think Main is the proper place to put the item.
If the poster is wanting the members to look in their stashes, then I think the Yard Sale section would be a better to place to post the item.