Methods, systems, and apparatus, including computer programs encoded on computer storage media, for analyzing user profiles. One of the methods includes identifying websites with which users of a social networking service have established an affiliation. The method includes filtering the identified websites by removing websites in which a count of users who have established an affiliation with the website exceeds a threshold. The method includes producing a list of valid affiliations for each filtered website, including generating a validity score for each of the established affiliations with the respective filtered website, determining whether each of the established affiliations with the respective filtered website is valid based on the corresponding validity score, and ranking the users who established valid affiliations with the respective website based on the corresponding validity scores. The method also includes providing the list of the valid affiliations ordered by the ranking.