1. A computer-implemented method for evaluating the supply of electronic content on an electronic network, the method comprising: receiving search results history for a plurality of queries by users for at least one keyword; determining, with at least one processor, a search results variability of the search results history for the plurality of queries for at the least one keyword, wherein determining the search results variability includes calculating a number of unique results contained in the search results history for the plurality of queries for the at least one keyword; determining, with the at least one processor, a supply value indicative of a supply of electronic content on the electronic network relating to the at least one keyword, based on the determined search results variability; and making available, over the electronic network, additional supply of electronic content relating to the at least one keyword based on the determined supply value.