SpamAssassin tags your email so that you can filter and delete messages that might be spam. While this service is optional and not enabled by default, we recommend that you use it if you get a lot of spam. Keep in mind, however, that the filter is not perfect, so you should do at least a cursory check of your suspected spam before deleting it.
For information on configuring SpamAssassin's settings, or enabling spam filtering with non-IMAP mail clients, you can refer to our March 14 column at http://www.mit.edu/~asksipb/2003columns/2003-03-14-spamassassin/ and the I/S Spam Screening web page at http://web.mit.edu/is/help/nospam/.
If you're using zwgc, the default zephyr client, you can do this by typing:
Then, to remove the old subscription:
athena% zctl add mail inbox %me%
For more information on zephyr, you can refer to our August 27, 2003 column at http://www.mit.edu/~asksipb/2003columns/2003-08-27-zephyr/.
athena% zctl del mail \* %me%
This method analyzes messages considered spam and non-spam (called "ham"), and records what words are found in each. When new mail comes in, it analyzes the words in the message and uses the previously recorded statistics to determine whether the message is spam. This method allows the filters to be constantly updated, and is generally very effective.
For a more detailed look at this method, refer to Paul Graham's "A Plan for Spam" at http://www.paulgraham.com/spam.html, and MIT's Information Technology Architecture Group's presentation on the topic at http://web.mit.edu/itag/seminars/20031210.html.
To do so, if you are using a graphical mail client, drag the message into the folder with your mouse. If you are using Athena Pine, press S (for Save), and then type Spamscreen.
Conversely, if a legitimate message ends up in the Spamscreen folder, you should train the filter so that it can avoid making the same mistake in the future. To do so, create a Hamscreen folder in your INBOX. Then, copy the legitimate message into the Hamscreen folder, and the filter will be trained with the message that night.
In both cases, after at least one night has passed, you can go back and delete these messages from the Spamscreen and Hamscreen folders as they are no longer needed. Note that all of MIT shares a common Ham and Spam training database, so you will also benefit from other users' training.