The document discusses what blockchains are and how they could potentially be used in business marketing. It explains that blockchains are distributed digital ledgers that can record transactions and other data across networks, providing real-time access and verification without third parties. Some ways blockchains may benefit businesses include enabling real-time payments, verifying ad delivery, and enhancing loyalty programs through automatic rewards redemption. The document notes that blockchains represent a new core technology with many potential future applications.