1. A method comprising: storing, in a social networking system, associations between a plurality of users and a plurality of objects maintained by the social networking system; identifying a target object maintained by the social networking system; identifying users associated with the target object from the stored associations; determining an affinity of each of the identified users for the target object; generating an influence metric associated with the target object based on the affinities, the influence metric representing a relevance of the target object to the identified users as a whole; and storing the influence metric.