1. A process implemented by a computing device, the process comprising: obtaining data indicating that authors in a social media system provided links to network content to other users of the social media system; based on statistical analysis of the data, ranking individual authors of the social media system according to their propensity to provide individual links to corresponding network content that becomes popular with the other users of the social media system, the ranking comprising: defining author scores of the individual authors, defining document scores of the individual links, determining corresponding chronological orders in which the individual authors of the social media system provided the individual links to the other users of the social media system, determining respective popularities of the individual links, updating the document scores using the author scores, the chronological orders in which the individual links were provided by the individual authors, and the respective popularities of the individual links to generate update document scores, and updating the author scores using the updated document scores, the chronological orders in which the individual links were provided by the individual authors, and the respective popularities of the individual links to generate updated author scores; and outputting a ranked list of the individual authors based on the updated author scores.