21. A computer program product, encoded on one or more non-transitory computer storage media, comprising instructions that when executed by one or more computers cause the one or more computers to perform operations comprising: receiving a user context of a user, wherein the user context specifies a location of a user device being used by the user; obtaining user activity data organized into sessions, each session being data representing a plurality of user activities performed by a distinct user during a respective time period, the sessions including sessions for multiple users; obtaining matching sessions for the received user context, each matching session being a distinct session that includes data representing activities performed by respective users having a user context matching the received user context during a time period represented by the matching session; obtaining general sessions, each general session including data representing activities performed by respective users during a time period represented by the general session; determining, from the obtained matching sessions and the obtained general sessions, one or more context-relevant activities that occur in the matching sessions more frequently than the one or more context-relevant activities occur in the general sessions, the one or more context-relevant activities being activities performed by users matching the received user context more frequently than by users in general; and providing information related to the one or more context-relevant activities in response to receiving the user context.
21. A computer program product, encoded on one or more non-transitory computer storage media, comprising instructions that when executed by one or more computers cause the one or more computers to perform operations comprising: receiving a user context of a user, wherein the user context specifies a location of a user device being used by the user; obtaining user activity data organized into sessions, each session being data representing a plurality of user activities performed by a distinct user during a respective time period, the sessions including sessions for multiple users; obtaining matching sessions for the received user context, each matching session being a distinct session that includes data representing activities performed by respective users having a user context matching the received user context during a time period represented by the matching session; obtaining general sessions, each general session including data representing activities performed by respective users during a time period represented by the general session; determining, from the obtained matching sessions and the obtained general sessions, one or more context-relevant activities that occur in the matching sessions more frequently than the one or more context-relevant activities occur in the general sessions, the one or more context-relevant activities being activities performed by users matching the received user context more frequently than by users in general; and providing information related to the one or more context-relevant activities in response to receiving the user context. 26. The computer program product of claim 21 , wherein the context-relevant activities comprise users issuing search queries for one or more restaurants, and wherein providing information related to the one or more context-relevant activities comprises providing information about the one or more restaurants.