Before the age of the ballpoint pen, Americans wrote with fountain pens dipped in ink. In the first half of the 20th century, clerks and others using fountain pen faced the problem of ink smearing. Consequently, offices and homes needed a way to keep freshly written words from smearing. Thus the ink blotter.
Ink blotters were small cards of soft, absorbent paper. They were universally common in every home and office in America. Once a way to adhere printable paper to blotting paper was patented in 1885, publishers rushed to create desktop advertisements for everything from cough drops to colleges. Usually made of a soft absorbent paper and formed into a card, ink blotters were used to dry up excess ink.
Ink blotters were a very popular form of advertising that were often given away by fountain pen manufacturers, banks, merchants and especially insurance companies. Blotters became by far the most widely used advertising novelty of the early 1900s, as common as business cards are today.
With the invention of the ballpoint pen in the 1950s, fountain pens became uncommon, and ink blotters disappeared from most office desks. Some vintage blotters, made in the 1930s and 1940s, are very highly prized and sought after collectibles.