Customer loyalty programs have been around since the late 18th century, when some U.S. merchants began giving their customers copper tokens that could be redeemed for future purchases. Today, similar rewards schemes are nearly ubiquitous, ranging from airline frequent flier programs to grocery store discount cards. Research has shown that these programs build brand loyalty and increase sales. They're undeniably popular: In 2016, American consumers held $195.4 billion in loyalty program points.