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.
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. 26. The system of claim 20 , further comprising accessing a social graph comprising a plurality of nodes and a plurality of edges connecting the nodes, each of the edges between two of the nodes representing a single degree of separation between them, wherein a first user of the mobile-client system corresponds to a first node in the social graph and the plurality of candidate place-entities corresponds to a plurality of second nodes in the social graph, respectively.