I think we'd totally need an active moderator able to remove the clutter. A few examples:
-close those threads in the "wanted" section when the person is not looking anymore or anything else by request and move them to a specific "archive" section if there's no way to delete them.
-make sure that every thread is in the right place and not in the wrong section
-delete double/triple posts with the same title and body if the person opens a new one for the same thing everyday.
-the advertisement section - I see people opening multiple threads everyday for every cat they want to sell and that causes extreme congestion. A moderator will make sure all their cats are listed in the same thread to give everyone equal opportunities without reading 560 pages in a day.
Thank you for listening!