When designing a product, Intercom's design principle of "Connected, Modular Systems" emphasizes focusing on the system as a whole, rather than individual interaction or visual designs. This approach ensures that important decisions are made at a high level, without getting bogged down in minor details. By creating systems first, teams can increase efficiency and reduce costs by reusing components across multiple contexts. The principle also highlights the importance of modularity, which allows for varying feature capabilities across separate systems to be addressed more efficiently. Furthermore, connected systems enable differentiation from competitors through seamless integration and strategic advantages such as a business moat. By applying this design principle, teams can build successful products that focus on the right questions and deliver value to customers.