A loyalty program is a marketing strategy designed to encourage customers to continue to shop at or use the services of a business associated with the program. Today, such programs cover most types of commerce, each having varying features and rewards schemes, including in banking, entertainment, hospitality, retailing and travel. Loyalty programs have been described as a form of centralized virtual currency, one with unidirectional cash flow, since reward points can be exchanged into a good or service but not into cash.