A method for retrieving information may include receiving a search query within an information retrieval system. Search results responsive to the search query may be identified from a first information corpus and a second information corpus. Search results responsive to the search query may be identified from a third information corpus. A ranking signal associated with the first information corpus and the second information corpus may be determined based on the search results from the third information corpus. The search results from the first information corpus and the second information corpus may be ranked based on the ranking signal.