A query received from a user is directed to a particular search application (e.g. an Enterprise search portal) that is associated with a result source from which to retrieve results. The received query may be federated to additional result sources when the received query is determined to be a popular query in a result source. Query logs associated with the additional result sources are analyzed to determine when a query is popular as compared to the original result source. The query may be altered before being executed that uses one or more of the additional result sources. When the query (altered/unaltered) is determined to be popular for any of the additional result sources as compared to the original result source, the query is executed using that additional result source.