During WW2 with troops just about everywhere mail to & from home was a daily problem. Just imagine how much there was. To solve at least part of the problem the military came up with Victory-Mail. By using a standardized form letter and limiting letters to one sheet per mailing. Regional postal centers processed reduced them to micro-film, shipped it to the US, Britain & other allies and reversed/re sized and printed the letters and placed them in the mail. Thousands of letters could be reduced to the size of an old movie canister, thereby saving cargo space and fuel.
More of the story here:
http://www.postalmuseum.si.edu/exhi...a_vmail.html
