"there is less competition per poster"
I totally agree. We have 6,750 registered bidders (compared to eBay's millions and Heritage's hundreds of thousands), but our bidders only have one ID each, and every one of them is a movie paper collector, and I don't think there is the slightest chance the other sites have nearly as many movie paper bidders as we do.
We will soon be purging our list of those who have not bid in a year, and that may well knock 1,000 or more off the roll. We have no interest in promoting an unrealistic number of bidders, any more than we are willing to have even a single result on our site where the price was not paid in full in cash by a real buyer.
Bruce