Lamarr and Anthiel received a patent in 1941, but the enormous significance of their invention was not realized until decades later. It was first implemented on naval ships during the Cuban Missile Crisis and subsequently emerged in numerous military applications.
Cash back credit card reward programs started out rather simply, offering a flat percentage rate (typically 1 percent of purchases) rebated back to the customer in the form of a check at the end of the year or a statement credit.
We wonât explain the basics of how credit cards work right here, but the late payers make it easy for the rest of us to ride free. With 107 million American Express cardholders charging almost $1 trillion last year, thatâs a lot of revolving credit. (For related reading, see: How Credit Card Delinquency Works .).