There are times when you will only have limited access to e-mail, and unable to respond as quickly as you normaly would.  If you are in a meeting, out of town, on vacation, etc.  You can use the 'Automatic Replies' feature in Outlook to create a detailed message that will be sent to anyone who sends you an e-mail message.  There is a setting you can select that will ONLY send Automatic Replies to "My Contacts Only".  This will send replies ONLY to names that are in your Contact folder.