The Greatest Generation. Their steady letters, by mail or computer, assert a loving presence as a powerful role model. Their experiences of the last turbulent decades have given them valuable perspective on the culture they now share with young people. An older friend of any age is simply a youngster's crucial link to history. You can probably recall how exciting it was to get your first personal mail.
Children often save letters as a sign of their own importance.
A letter means you are thinking of the child, you took the time to write, and you hope for a reply. Sharing words bonds people, just like sharing food. Another benefit of writing is the subtle influence your notes can exert. Unlike parents and teachers, seniors need not tell kids what they can and can't do. Instead, they have the pure joy of freedom from any disciplinary role.