Until the mid-19th century, personal correspondence was mailed in a sealed envelope. In the late 1850s, the notion of sending a short message on a card took hold. Not everyone was thrilled with the lack of privacy. It seemed improper to send a message that anyone—mailmen, curious family members, even servants—could read.

In 1861, John Charlton of Philadelphia copyrighted a private postal card, later selling the copyright to H.L. Lipman who printed and sold Lipman's Postal Cards. The card had no picture. It had decorative border on the message side and address lines and box for a stamp on the mailing side. (Writing a message on the mailing side was prohibited until 1907.) The card mailed at the same 2-cent rate as a first class letter.

The popularity of the format prompted the U.S. Postal Service to begin printing postcards in 1873. While privately produced cards still required 2 cents to mail, the Postal Service cards could be mailed with only 1 cent in postage. In addition, only the Postal Service could use the term postcard.

On May 1, 1893 the illustrated souvenir card commemorating the World's Columbian Exposition in Chicago further captured the public imagination. By May 19, 1898, the Private Mailing Card Authorization Act allowed private manufacturers' cards to mail at the rate of 1 cent. In 1901, private companies were allowed to use the term postcard. In 1907, writing was permitted on the mailing side and postcards were printed with divided backs. By the mid 1900s, millions of postcards were being sent.

The simple postcard remains a staple of personal communications. It is sent from vacations, as a reminder and for birthdays. The postcard is uniquely tactile, easy to save as a souvenir and post on a refrigerator, bulletin board or cubicle wall. It's also appealing because it requires less time to write and less money to mail.