Disclosed are systems and methods for detecting unwanted electronic message transmissions on a communications network. These include establishing a database for storing metadata associated with message traffic according to at least the source addresses of the senders of electronic message transmissions. The disclosed principles also include monitoring electronic message transmissions at the certain location on the electronic communications network. Also, included is populating the database with metadata derived from analysis of the monitored electronic messages, where the metadata includes metadata derived by analyzing the contents of the monitored electronic messages. Based upon the populated database, it is determined whether certain received electronic messages are likely to be unwanted based on an examination of the metadata associated with the source addresses of the senders of the received electronic messages and based on the analysis of the content of monitored electronic messages at least in part without reference to a promulgated database of “signatures” of known unwanted electronic messages.