Never enter the complete address of the individual into the distribution list when you create it. Always create the individual's entry first; then, when you go to construct your distribution list, simply select the individuals' name from the list that's presented. The reason for doing it this way is that if an individual's e-mail address changes and you have both a personal (individual) entry for them and have that person's e-mail address and not simply their name in one or more distribution lists, if you update their individual entry, it won't be updated in the distribution list. On the other hand, if you've selected a pre-existing Address Book entry for inclusion in the distribution list, when the individual, pre-existing entry gets updated, so will the distribution list. Otherwise, when you send Aunt Mary an individual e-mail, she'll receive it, but when you send a message to your entire family and haven't remembered to update her address in the family distribution list, she won't receive it.