TY - CONF ID - www200925 UR - http://www2009.eprints.org/25/ A1 - Aggarwal, Gagan A1 - Muthukrishnan, S. A1 - Pál, Dávid A1 - Pál, Martin Y1 - 2009/04// N2 - In sponsored search, a number of advertising slots is available on a search results page, and have to be allocated among a set of advertisers competing to display an ad on the page. This gives rise to a bipartite matching market that is typically cleared by the way of an automated auction. Several auction mechanisms have been proposed, with variants of the Generalized Second Price (GSP) being widely used in practice. There is a rich body of work on bipartite matching markets that builds upon the stable marriage model of Gale and Shapley and the assignment model of Shapley and Shubik. This line of research offers deep insights into the structure of stable outcomes in such markets and their incentive properties. In this paper, we model advertising auctions in terms of an assignment model with linear utilities, extended with bidder and item speci?c maximum and minimum prices. Auction mechanisms like the commonly used GSP or the well-known Vickrey-Clarke-Groves (VCG) can be interpreted as simply computing a bidder-optimal stable matching in this model, for a suitably de?ned set of bidder preferences, but our model includes much richer bidders and preferences. We prove that in our model the existence of a stable matching is guaranteed, and under a non-degeneracy assumption a bidder-optimal stable matching exists as well. We give an algorithm to ?nd such matching in polynomial time, and use it to design truthful mechanism that generalizes GSP, is truthful for pro?tmaximizing bidders, correctly implements features like bidder-speci?c minimum prices and position-speci?c bids, and works for rich mixtures of bidders and preferences. Our main technical contributions are the existence of bidder-optimal matchings and strategyproofness of the resulting mechanism, and are proved by induction on the progress of the matching algorithm. TI - General Auction Mechanism for Search Advertising SP - 241 M2 - Madrid, Spain AV - public EP - 241 T2 - 18th International World Wide Web Conference ER -