1. A method, comprising: a first computer system storing electronic product advertisements corresponding to products from two or more providers, wherein the electronic product advertisements are associated with respective values that are indicative of one or more time periods during which ones of the electronic product advertisements are active; the first computer system determining a set of currently active product advertisements from the plurality of electronic product advertisements based on the associated respective values; the first computer system receiving a query specified by a consumer, wherein the query includes one or more search terms; the first computer system matching the query against the set of stored currently active product advertisements, wherein said matching uses one or more of the search terms and produces one or more matched advertisements; and the first computer system sending at least one of the matched advertisements to a second computer system, wherein the sent advertisements are displayable on the second computer system in response to the query, and wherein the sent advertisements include at least a first advertisement advertising a website associated with a first of the two or more providers.