All mailing list administrativia MUST be sent to a *-request address, never to the list itself. For email@example.com, for example, send mailing list requests to firstname.lastname@example.org. Mail sent to the *-request address can have one of the following words in the Subject header:
Most (un)subscription requests are processed automatically without human intervention. Do not send multiple (un)subscription or info requests in one mail. Only one will be processed per mail.
The *-request server usually does quite a good job in discriminating between (un)subscribe requests and messages intended for the maintainer. If you for some reason would like to make sure a human reads your message, make it look like a reply (i.e. the first word in the "Subject:" field should be "Re:", without the quotes of course); the *-request server does not react to replies.
In the event of an address change, first send an unsubscribe for the old address (this can be done from the new address), and then a new subscribe from the new address (the order is important).
Two lists, email@example.com and firstname.lastname@example.org, are also available in digest form, which allows you to receive all messages of the day combined into one message. You can subscribe to these by sending mail to email@example.com or firstname.lastname@example.org.