Abstract: A method for enforceably reducing spam comprises checking an email message for a specific mark and if the specific mark is present, tagging the email message as non-spam. The tagged email is displayed to a user of a local computer. The specific mark may be displayed with the tagged email. The mark is part of an enforceable anti-spam email header field comprising a field name and a field body. The field body comprises the mark which is used for identification or indication of ownership. The mark is legally reserved for the exclusive use of the owner of the mark. If the user identifies the tagged email as spam, the tagged email is sent to a remote enforcement computer.