1. A method for ranking search results received from a plurality of distinct search resources, the method comprising: receiving from each of a plurality of search resources, a set of ranked search results, wherein each search result identifies an item and wherein each search result includes metadata characterizing the item; determining, by a computer processor, a unified ranking for the search results, wherein the unified ranking maintains a relative ranking of each set of results as received from the plurality of search resources, wherein a ranking of a first result in the unified ranking is determined based on metadata of the first result and metadata of each second result having a lower rank than the first result in the associated set of results; and ordering the search results by the determined unified ranking.