Techniques are provided for modifying queries to increase the number of sponsored links that are returned in response to the queries. A query modification system uses a predefined set of rules that are designated to modify a query to increase the chance that the modified query will match more sponsored links. The modified query is then matched against a listing of search query strings that have been pre-selected by sponsors. Each pre-selected search query strings corresponds to one or more sponsored web links. If the modified query matches one of the pre-selected search query strings, the corresponding sponsored web links are returned and displayed to the user.