A distribution list is a collection of contacts. It provides an easy way to send messages to a group of people. For example, if you frequently send messages to the marketing team, you can create a distribution list called Marketing Team that contains the names of all members of the marketing team. A message sent to this distribution list goes to all recipients listed in the distribution list. Recipients see their own names and the names of all other recipients on the To line of the message instead of seeing the name of the distribution list. You can use distribution lists in messages, task requests, meeting requests, and other distribution lists.
You can easily add and delete names in a distribution list, send it to others, and print it.
Distribution lists are identified with 
and are stored by default in your
Contacts folder, so you can sort and assign categories to them.
If you use Microsoft Exchange Server, your Global Address List
can contain
global distribution lists, which
are available to everyone who
uses that network. The personal distribution lists
that you create in your Contacts folder are available
only to you, but
you can share them by copying and sending
them
to others.