How to update your Christmas card list

I saw this at Shirley Hornbeck's Genealogy Tips, #2:

FINDING LIVING RELATIVES:

To contact a living person whom you have lost, write a letter to the person, be sure to include your address and telephone number in the letter. Send the letter in an unsealed stamped envelope, along with a cover letter to the Social Security Administration, Letter Forwarding Unit, 6401 Security Blvd., Baltimore, MD 21235. Include in your cover letter as much as you know about the person: Name, Social Security number, birthplace, birth date, name of the person's parents. You do not have to know all of the information, but the process will be quicker if you give more identifying information. If the person you are seeking is listed in the SSA files, the letter will be forwarded to them and it's up to that person to contact you.

If they owe you money, don't hold your breath.