1. A method performed by one or more processing devices, the method comprising: identifying online resources with which users of a social networking service have established an affiliation; identifying a subset of the online resources in which a count of users who have established an affiliation with the online resource exceeds a threshold; producing a list of valid affiliations for each online resource of the subset of online resources, comprising: generating a validity score for each of the established affiliations with the respective online resource, determining whether each of the established affiliations with the respective online resource is valid based on the corresponding validity score, and identifying a subset of the users who established valid affiliations with the respective online resource based on the corresponding validity scores; and providing the list of the valid affiliations based on the identified subset of users.