Reading this initial post from 2006 sure makes me long for the good old days. The "marketplace" being referred to here is the Forum Only Selling Area -- not ebay, ComicConnect, ComicLink, Heritage, or any other non-Board commercial venue.
If you're protesting to me, I always thought the purpose of this thread was to notify people of sales going on outside the GA forum, mainly because many GA collector's don't venture outside the GA forum.
While yes, it was originally meant for the Forum Only selling area, I see no reason why someone can't notify people about other venues.