Intercom's 9 fundamentals of great interaction design aim to guide designers in creating a seamless user experience. The fundamentals focus on establishing hierarchy, creating visual rhythm and balance, using commonly accepted patterns and interactions, progressive disclosure, clarity and concision, responsiveness and speed, guiding users to what they should do next, and being mindful of accessibility. These principles are designed to help designers create interaction designs that prioritize customer needs and business outcomes, while avoiding common pitfalls such as overwhelming users or introducing unnecessary complexity. By following these fundamentals, designers can build excellent customer-focused software that sets a baseline for interaction design quality.