As you can see, a carbon copy of the message (the Cc: header entry) was sent to the postmaster of Widener's CS department. The Postmaster is responsible for maintaining a reliable mail system on his system. Usually postmasters at sites will attempt to aid you in getting your mail where it's supposed to go. If a typing error was made, then try re-sending the message. If you're sure that the address is correct, contact the postmaster of the site directly and ask him how to properly address it.
The message also includes the text of the mail, so you don't have to retype everything you wrote.
——- Unsent message follows ——-
Received: by cs.widener.edu id AA06528; Sat, 25 May 91 16:45:14 -0400
Date: Sat, 25 May 91 16:45:14 -0400
From: Matt Groening <mg@gracie.com>
Message-Id: <9105252045.AA06528@gracie.com>
To: lsimpson@cs.widener.edu
Subject: Scripting your future episodes
Reply-To: writing-group@gracie.com
…. verbiage …
The full text of the message is returned intact, including any headers that were added. This can be cut out with an editor and fed right back into the mail system with a proper address, making redelivery a relatively painless process.
Mailing Lists
People that share common interests are inclined to discuss their hobby or interest at every available opportunity. One modern way to aid in this exchange of information is by using a mailing list—-usually an email address that redistributes all mail sent to it back out to a list of addresses. For example, the Sun Managers mailing list (of interest to people that administer computers manufactured by Sun) has the address sun-managers@eecs.nwu.edu. Any mail sent to that address will "explode" out to each person named in a file maintained on a computer at Northwestern University.
Administrative tasks (sometimes referred to as administrivia) are often handled through other addresses, typically with the suffix -request. To continue the above, a request to be added to or deleted from the Sun Managers list should be sent to sun-managers-request@eecs.nwu.edu.
When in doubt, try to write to the -request version of a mailing list address first; the other people on the list aren't interested in your desire to be added or deleted, and can certainly do nothing to expedite your request. Often if the administrator of a list is busy (remember, this is all peripheral to real jobs and real work), many users find it necessary to ask again and again, often with harsher and harsher language, to be removed from a list. This does nothing more than waste traffic and bother everyone else receiving the messages. If, after a reasonable amount of time, you still haven't succeeded to be removed from a mailing list, write to the postmaster at that site and see if they can help.
Exercise caution when replying to a message sent by a mailing list. If you wish to respond to the author only, make sure that the only address you're replying to is that person, and not the entire list. Often messages of the sort "Yes, I agree with you completely!" will appear on a list, boring the daylights out of the other readers. Likewise, if you explicitly do want to send the message to the whole list, you'll save yourself some time by checking to make sure it's indeed headed to the whole list and not a single person.