What is the purpose of Contact List?
One of the advantages of using the Contacts list is that you can define your own aliases for the e-mail addresses you often use. You can do so using the following path:

The Information System My Mail Contacts

1 To open a window for composing a new message pre-filled with an e-mail address, click on the appropriate alias.

When composing a new message, enter the recipient's alias into the “To:” field, click on Contacts or show Contacts situated next to Search and select the recipient.

You can also compose a message directly from the Contacts list by using the following path:

The Information System My Mail Contacts

To open a window for composing a new message pre-filled with the recipient's address, click on his/her alias.