13. A computer storage medium encoded with a computer program, the program comprising instructions that when executed by data processing apparatus cause the data processing apparatus to perform operations comprising: identifying one or more queries that were received with a reference to a given factual entity, wherein the one or more queries identified for the given factual entity are different from one or more queries identified for one or more other factual entities; identifying one or more resources related to the given query; obtaining search results that are responsive to a received query; determining that the given factual entity is referenced by the received query; identifying a type of entity for the given factual entity; identifying, from a set of different knowledge panel templates, a knowledge panel template specified for the type of entity, the identified knowledge panel template including placeholders for content relevant to the type of entity; selecting, from the one or more resources related to the given factual entity, content for display in a knowledge panel for the given factual entity, the selected content including a first content item obtained from a first resource and a second content item obtained from a second resource different than the first resource, each given content item of the selected content being selected based on a number of the one or more received queries that reference both (i) the given factual entity and (ii) information presented by the given content item; generating the knowledge panel for the given factual entity by populating the placeholders of the identified knowledge panel template with the selected content; and providing data that causes the identified search results and the knowledge panel to be presented on a search results page, the knowledge panel presenting the selected content in a knowledge panel area alongside at least a portion of the search results.
13. A computer storage medium encoded with a computer program, the program comprising instructions that when executed by data processing apparatus cause the data processing apparatus to perform operations comprising: identifying one or more queries that were received with a reference to a given factual entity, wherein the one or more queries identified for the given factual entity are different from one or more queries identified for one or more other factual entities; identifying one or more resources related to the given query; obtaining search results that are responsive to a received query; determining that the given factual entity is referenced by the received query; identifying a type of entity for the given factual entity; identifying, from a set of different knowledge panel templates, a knowledge panel template specified for the type of entity, the identified knowledge panel template including placeholders for content relevant to the type of entity; selecting, from the one or more resources related to the given factual entity, content for display in a knowledge panel for the given factual entity, the selected content including a first content item obtained from a first resource and a second content item obtained from a second resource different than the first resource, each given content item of the selected content being selected based on a number of the one or more received queries that reference both (i) the given factual entity and (ii) information presented by the given content item; generating the knowledge panel for the given factual entity by populating the placeholders of the identified knowledge panel template with the selected content; and providing data that causes the identified search results and the knowledge panel to be presented on a search results page, the knowledge panel presenting the selected content in a knowledge panel area alongside at least a portion of the search results. 18. The computer storage medium of claim 13 , wherein the instructions, when executed by data processing apparatus, cause the data processing apparatus to perform further operations comprising: determining that the received query is associated with multiple distinct meanings; and identifying content related to each of the distinct meanings, wherein the knowledge panel includes content for two or more of the distinct meanings, the content for at least one of the distinct meanings including a content item that includes a link that, when selected, initiates a search for search results related to the at least one distinct meaning.