Regulating electronic mail

摘要

A method and system are disclosed which regulate the electronic mail received by a subscriber or user by forcing the sender to pay a small amount for sending e-mail, making it uneconomic to send very large volumes of 'spam' indiscriminately. The resulting 'permit' or stamp can be reused by the receiver. A method and system for managing the response to unstamped e-mail is also disclosed, which may use a 'white-list' or 'challenge' the sender to determine they are human and not a junk mailer.