Understanding Refer Earn Apps: A Complete Guide Refer Earn Apps, which capitalize on online word-of-mouth advertising, have grown in popularity as a digital marketing toolslots 51 bonus. By providing rewards to both the referrer and the new client, these applications encourage users to suggest goods or services to their social network. Usually, when two users share a special link for registration or a purchase, both parties get rewarded—bonuses, discounts, or money—when someone uses the link to sign up or make a purchase.