The majority of lists use the Listserv software by LSoft Int. Inc. and allow individuals to subscribe by sending commands to the listserv address. This tells listserv to ignore all that follows so that it does not try to interpret your signature file as commands.
Some list are private and subscribers can only be added by the listowner.
When you send the above command to listserv and the list is a private list the request if forwarded to the list owner for their approval prior to you being added to the list. Now that you know how to subscribe to a list you may want to be able to unsubscribe from a list as well. To unsubscribe you send mail to listserv's address with the unsubscribe command. These two commands are just a few of the many that can be used with a list that uses the Listserv software. For a complete User's Guide go to Listserv Manuals .