A method and system for parsing and analyzing incoming electronic mail messages to determine a confidence factor indicative of whether or not the messages are junk e-mail. The method and system utilize message services which attempt to contact the purported sender in order to verify that the identified host computer actually exists and accepts outgoing mail services for the specified user. The routing history is also examined to ensure that identified intermediate sites are also valid. Likewise, seed addresses can alert an e-mail provider to potential mass mailings by reporting when mail is received for ghost or non-existent accounts.