The document discusses discounts, vouchers, and referral programs in e-commerce applications. It covers the purpose and importance of these strategies in attracting customers and boosting sales. Examples are provided of discounts like Amazon Prime Day and flash sales. Vouchers include discount, gift, and promotional vouchers. Referral programs leverage existing customers through bonuses and friend discounts. The technical aspects of creating and managing these features in e-commerce apps and backend systems are also outlined.