A method and system are provided for allowing an electronic mail user to
block receipt of undesirable electronic mail content. An email user
contacts her email service provider via an Internet-based web page. The
user may designates certain keywords or text strings and certain email
addresses associated with email she considers undesirable. Subsequently,
when email messages are sent to the user, those messages are intercepted
by the user's email service provider at an email server. A database
lookup is performed for the keywords, text strings or email addresses
designated as undesirable by the user. The email service provider does
not deliver email containing or from the designated undesirable keywords
or text strings and certain email addresses. The user may designate a
return message to be sent back to the sender of the undesirable email to
alert the sender not to send future messages to the user containing the
undesirable keywords or text. If desired, in an effort to cause the
sender to abandon the user's email address as a target for unsolicited
and undesirable email, the email service provider may send a return
message to the sender that indicates that the user's email address is not
operable and that the email to the user is undeliverable.