1. A computer-implemented method, comprising: maintaining, by a social networking system, a plurality of personas describing an entity in the social networking system, each persona associated with a page provided by the social networking system; receiving, by a social networking system, web traffic directed to one or more personas by one or more external systems, wherein the traffic directed to the one or more personas is originated via a link or a hyperlink in the external system; determining a measure of authenticity of a persona based on the web traffic directed to the persona by the one or more external systems, the measure of authenticity of the persona comprising a weighted aggregate of authenticity scores of each of the one or more external systems, wherein the weight of each of the one or more external systems is based on an amount of traffic directed to the persona by the external system; determining that a persona representing the entity is authentic if the measure of authenticity of the persona indicates higher web traffic being directed to the persona by the one or more external systems compared to other personas representing the entity; and storing information indicating whether the persona is authentic.