1. A computer-implemented method performed on a first computer for displaying on a screen coupled to a second computer, an optimized placement of search result listings displayed in a search Web page, the method comprising: said first computer measuring an actual performance of each listing in a set of listings located in one or more Web pages containing a search term and a search result corresponding to the search term, wherein the actual performance comprises at least one of click-through rate (CTR) and context of the listing, and wherein the set of listings includes a plurality of listings; assigning an expected performance for each listing in the set of listings based on their respective locations, wherein the expected performance comprises a user defined expected CTR and the context of the listing; determining an average expected performance for the set of listings; tiering the average expected performance of the set of listings based at least on the number of listings in the set of listings to produce a tiered expected performance for the set of listings, wherein the average expected performance is increased when the set of listings includes more than a predefined number of listings and the average expected performance is decreased when the set of listing includes less than a predefined number of listings; determining an overall average performance for the set of listings based on the actual performance for each listing in the set of listings; promoting the set of listings to a more prominent location when the overall average performance of the set of listings indicates that overall the actual performance of the listings in the set of listings is better than the tiered expected performance of the set of listings; demoting the set of listings to a less prominent location when the overall average performance indicates that overall the actual performance of the set of listings is poorer than the tiered expected performance of the set of listings; and displaying a listing from the set of listings at the more prominent location or at the less prominent location.