Google adwords is a well known application of algorithmic game theory. It has a system wherein buyers of ad placements bid to put their ads up on various sellers websites, then pay the second bid below them.
If this system were turned on its head, and sellers of ad placements (websites, in other words) bid to be the cheapest space (relative to their quality) for buyers of ads and were paid the second cheapest price instead, would this result in the same prices being paid for ad placements?
If these two scenarios are not equivalent, where is the breakdown?
In general, is there any duality between these problems?