In the 1860s, the postcard swept the Austro-Hungarian empire. This new technology was quick, informal, and cheap; by the turn of the century, it had gone viral. Small cards were whipped up by emerging artists — as a democratic art form. They became tiny canvases of historical proportions, providing snapshots of cultural life, social change, advertising, and propaganda.

It wasn't until recently that email, video, Facebook, and other social media took over as the precious connection between travelers and their loved ones back at home. Today the postcard is seen as a beloved memento of slow travel, a low-fi reminder of the simple pleasure of capturing a moment in time.

And now Leonard A. Lauder, billionaire son of Estée, is showcasing highlights from his incredible collection of postal ephemera (numbered around 100,000) for The Postcard Age ($45), a book and corresponding show (through April 14, 2013) at the Museum of Fine Arts, Boston.

Next: See a selection of our favorite postcards.