LOYALTY CARDS
A loyalty card program is an incentive plan that allows a retail business to gather data about its customers. Customers are offered product discounts, coupons, points toward merchandise or some other reward in exchange for their voluntary participation in the program. A secondary goal of a loyalty card program is to build repeat business by offering participating customers something that isn't available to non-participating customers.

Loyalty cards often resemble plastic credit cards but they can also be keychain fobs, stickers, or tags. Typically a loyalty card has a barcode or magnetic stripe that's scanned at the point of sale (POS). The card identifies the customer and sends information about what the customer bought to a database. The information in the database is used to help the retailer understand and influence his customers' buying habits.