20. A system comprising: one or more processors; and a memory coupled to the processors comprising instructions executable by the processors, the processors operable when executing the instructions to: receive, from a mobile-client system of a first user, geographic-location information associated with the mobile-client system; calculate, for each of a plurality of candidate place-entities corresponding to the geographic-location information, a confidence score based on both the geographic-location information and social-graph information associated with the first user, wherein the confidence score represents a probability that the mobile-client system is located at the candidate place-entity; and send, to the mobile-client system, information associated with one or more of the candidate place-entities based on their respective confidence scores.
37. The system of claim 20 , wherein each candidate place-entity represents a particular physical place located at a particular geographic area.