These are some resources that you may find useful in learning more about postcards and how they’ve evolved and changed over the years. Happy mailing!
Postcard History Links
About Deltiology: The study and collecting of postcards. – Wikipedia
Working Military Mail – Smithsonian National Postal Museum
Postcard History – Smithsonian Institution Archives
How old is your postcard? – Chicago Postcard Museum
Postcard Dating (Postage rates, stamps)
Lost Greetings 