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.
Rotating Category Function. Credit cards set up a schedule for which types of purchases get you extra cash back. For example, your credit card might regularly give you 1 percent cash back on all purchases, but give you 5 percent cash back when you shop at grocery stores. Often, the credit cards use broad categories for the rewards, such as gas stations, restaurants, movie theaters or home improvement.