You're going to get a lot of hits. Experts attribute the growth in online auctions to this very ability to broaden the audience for many types of items. David Lucking-Reiley, a visiting professor at Kellogg, has published research on online auctions. He agreed that in certain respects sellers benefit, but said overall, the auctions are a boon to everyone. But auctions are less valuable for goods where it's obvious what the market price should be.
Auctions are more valuable when the demand is uncertain or fluctuating.
The way that I would think about it is that it is certainly true that if I wanted to sell something from my attic, and I didn't have the option of eBay, it's quite likely that I would not get as good a price. Certainly, competitive bidding benefits the seller. However, he also said the buyer gains by even having access to the item in the first place. Another advantage is that the venue allows the marketplace to determine the value for an object, which otherwise might be difficult to place, Lucking-Reiley said. Obviously, the buyer paid a huge premium.