On APUG, which I think uses the same software, you can 'close the thread' when the item is sold. Here on LFPF, the mods have that disabled, so the person posting the ad can't close it to further comments. I doubt the mods want to go and fiddle with 50 postings a day in the Classifieds but I have no idea why they disabled the 'close thread' feature for the original poster. I'm sure there is a logical reason for it.

Personally, I like the old ads there. I've learned heaps of things from them about many lenses and cameras.

Richard