A system is provided for allocating combinations of search results, types of space, and/or other information from different sources (e.g., search engines) in which a type of space, search results, and/or other information from at least one source or type or from each source or type, for example, are optimized to obtain an optimum commercial value. Using the example of a search, a commercial metric and a user satisfaction metric are established for search terms and used in the optimization process. In calculating the commercial value and the user satisfaction value for a set of search results, the weight given to the commercial value and the user satisfaction value of a search result is different depending on its source. Optionally, keeping the user satisfaction value above a certain threshold is treated as a constraint while optimizing the commercial value. Alternatively, a tradeoff may be allowed between the minimum threshold for the user satisfaction and a better commercial value. For example, a commercial value may be associated with the commercial metric and quality metric so that the total commercial value may be calculated and optimized.