1. A method of predicting users who will have a specified influence in a social network, comprising: identifying a set of users of the social network; identifying a subset of the users as influential users based on defined criteria; identifying a multitude of user behavior measures as predictors of which ones of the set of users are said influential users; forming a composite predictor model from said user predictor measures to determine which ones of the set of users will have a specified influence in the social network in the future, including using each of said measures to provide a respective one ranking of the influence in the social network of an associated group of users of the set of users; aggregating said respective one rankings to form an aggregate ranking of said associated group of the users; and using said aggregate ranking to predict which ones of the set of users will have a specified influence in the social network in the future.