This document discusses the importance of user experience (UX) design for startups. It explains that UX involves applying methods like interviews and usability testing to design products that provide a good experience for users. This helps startups "guess well" about how to achieve wide adoption of their products. The document recommends that startups get to know their users, build models of the user experience, prototype and test ideas with users before building full products, and test the final product with users. UX tools and methods can help startups align their efforts and make better guesses about what will lead to customer adoption.