To prevent this, most MUAs have the possibility to make use of an integrated electronic addressbook. Other tags can have values for postal address, phone number, etc. More advanced MUAs allow to define lists of E-mail addresses so that by giving one address, the mail will go to a whole list of addresses. Other advanced functions are updating the addressbook with the data you find in the header fields of an incoming mail. With the stdirect command you can activate this addressbook.
Some systems allow the integration of a shared and a private addressbook.