Abstract: A system for categorizing users based on activities in a social network analyzes behavior data of online social activities for each user of a set of users. The system generates a user activity log for each user of the set of users, where the user activity log for each user is generated based on the behavior data. The system determines a set of behavioral categories based on the users' activity logs, each behavioral category of the set of behavioral categories being defined by a set of values corresponding to the one or more social activities in the behavior data. The system also associates at least one user of the set of users with one behavioral category of the set of behavioral categories based on the set of values defining the one behavioral category and user activity log for the at least one user.