14. The system of claim 13 , wherein presenting the item listings positioned in the search results page based on the ranking score assigned to each item listing includes generating a list of the item listings ordered based on the ranking score assigned to each item listing such that the item listing assigned the highest ranking score is first in the list and the item listing assigned the lowest ranking score is last in the list.
13. A system comprising: a processor-implemented search engine module configured to process a query to identify item listings that satisfy the query, each item listing comprising data representing one or more attributes of a product or service offered for sale; a processor-implemented ranking score assignment module configured to assign a ranking score to each item listing that satisfies the query, the ranking score derived as the product of two or more component scores including a first component score representing a measure of relevance between search terms in the query and the item listing, the second component score being independent of the query and representing a measure of quality for the item listing, the measure of quality being based at least in part on at least one of (i) an attribute of the item listing determinable at a time of listing, or (ii) an observed sales performance of the item listing or an item listing similar thereto; and a processor-implemented presentation module to present the item listings that satisfy the query in a search results page, the item listings positioned in the search results page based on the ranking score assigned to each item listing.