A few people have commented about having an unmoderated for sale forum.
That sounds like a very good idea and rightly so.
However (and I am very happy to be corrected) in these litigeous politically correct times I dont think it is that simple. If you are the people putting up the forum you shoulder some of the liabilit whatever disclaimers you may publish.
For example, someone may advertise DC headsets when infact they are not - that is trademark violation and it would be up to the owners of the site to do something about it.
Unmoderated forums on which any one can post just dont work - and sadly you would be surprised what some would post.