A reader service card
or bingo card
is a reply card inserted in a magazine
and used by readers to request free samples and literature from businesses who advertised in the issue. Many advertisers are listed on the reply card. Readers circle the advertisers they are interested in and mail back the card to the publisher
who then provide their advertisers with the appropriate leads. In 1933 Thomas Register
began publishing Industry Equipment News (IEN). IEN became the first publication to include a "bingo reply card."