Shutterfly Is an Internet-Based Personal Publishing Service That Allows Consumers

Shutterfly is an Internet-based personal publishing service that allows consumers to upload and share photos and videos. They also allow customers to create photobooks, stationary, and cards. The company tries to differentiate itself from other companies that offer similar services by allowing customers to upload an unlimited number of photos at no cost. Explain why Shutterfly would offer such a service free of charge.