In one embodiment, a processor may identify information about an entity represented by a first node in a social graph for a social-networking system. The information may comprise a location for the entity and an affinity score for the entity with respect to a user, wherein the user is represented by a second node in the social graph. The processor may then determine a region defined with respect to the location of the entity, wherein the region is defined based in part on the affinity score for the entity, as well as determining that a location of a mobile device associated with the user is within the region. Finally, the processor may cause the mobile device to transition from a sleep state to an active state.