Systems and methods are provided for allowing subscriber message sending profiles to be maintained and used in conjunction with behavior-based anomaly detection techniques and traditional content-based spam signature filtering to enable application of appropriate message disposition policies to outbound subscriber message traffic. According to one embodiment, subscriber profiles are constructed for multiple subscriber accounts associated with a service provider based on outbound message flow originated from the subscriber accounts. Then, possible subscriber account misuse may be discovered by performing behavior-based anomaly detection, including a comparison of a subscriber profile associated with the subscriber account with recent subscriber account usage information, to identify one or more behavioral anomalies in outbound message flow originated from a subscriber account, the behavior-based anomaly detection.