1. A method implemented in a data processing apparatus, comprising: receiving a query from a member of an enterprise; searching an index that includes member information of members of the enterprise and resources of the enterprise, wherein: the resources include data describing entities and entity facts related to the enterprise and relationships among the entities; the entity facts are identified from the entities of the resources of the enterprise; each entity fact describes at least one feature of the entity that identifies corresponding relationships between the entities and members of the enterprise; and the index includes data defining access privileges to the data describing the entities and the entity facts according to respective entity fact access control lists; determining the entity facts that are accessible to the member according to the entity fact access control lists; determining, based on member information of the member and entity facts that are accessible to the member, search result data including data describing entities and entity facts relevant to the query; and providing search results, based on the search result data, to the member of the enterprise, the search results including data describing the entities and entity facts determined to be relevant to the query.