Just one further thought-- 20% off is most likely an across the board manufacturers deal, available everywhere. Maybe the new Forum could encourage postings that exceed 20% off (?), as it then likely is a real secret sale / hidden find.
One add-on to that, though, is that those kind of sales might actually be breaking agreements that the retailer has with the vendor, and . As consumers, that doesn't matter to us, but it could get a retailer in trouble with a vendor (especially a MAP vendor) if their secret sale gets back to the manufacturer, which could in turn result in that retailer losing the right to sell those items. For example, there's a certain item I picked up for my tank (a rather integral item to my build... perhaps the single most important item) that I'll never publicly say what I paid for it, because it was likely significantly below MAP, and I don't want to get the retailer in trouble by dropping even a breadcrumb of evidence. Most likely nothing would happen if I did, but would hate to put a retailer in hot water unnecessarily.