Many advertisers (bidders) use Internet systems to buy advertisements on publishers' webpages or on traditional media such as radio, TV and newsprint. They seek a simple, online mechanism to reserve ad slots in advance. On the other hand, media publishers (sellers) represent a vast and varying inventory, and they too seek automatic, online mechanisms for pricing and allocating such reservations. In this paper, we present and study a simple model for auctioning such ad slots in advance. A monopolist seller owns a set of slots that it will display at some point T in the future. Until T, bidders arrive sequentially and place a bid, demanding a reservation for one slot out of a set of desired slots. The seller must decide immediately whether or not to grant a reservation. Our model allows the seller to cancel at any time any reservation made earlier. If the seller cancels bidder i's reservation, i incurs a utility loss amounting to a fraction of its value for the reservation. Ou...
Florin Constantin, Jon Feldman, S. Muthukrishnan,