1. A computer-implemented method, comprising defining a category comprising one or more terms; generating a query based on said category, wherein said generation step is performed in response to said defining step; sending said query to a plurality of information sources, wherein each information source comprises a plurality of information entities; obtaining results from said plurality of information sources; and ranking said plurality of information sources based on scores for results returned by said plurality of information sources in response to said query to obtain a ranked list of information sources associated with said category.