15. The system of claim 12 , wherein selecting the proper subset of the search queries based on the similarity scores comprises: selecting a proper subset of the second users, the subset of the second users comprising second users for which a corresponding similarity score exceeds a threshold similarity score; and selecting the search queries submitted by the second users in the proper subset of the second users as the subset of the search queries.
12. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: obtaining first profile data for a first user that is associated with a computing device; obtaining second profile data for second users that submitted search queries, the second users being different from the first user; determining, based on the first profile data and the second profile data, similarity scores that are each indicative of a degree of similarity between the first user and at least one of the second users; selecting a proper subset of the search queries based on the similarity scores; generating an update for an autocomplete cache of the computing device associated with the first user using the selected subset of the search queries; and providing the update to the computing device associated with the first user.