This document discusses the differences between startups and small businesses, and outlines the customer development process that startups should follow to search for a viable business model. It notes that most startups fail due to a lack of customers, not due to product failures, and that founders are often wrong in their assumptions about what customers want. It advocates getting out of the building to test hypotheses with real customers from the beginning, rather than following a traditional product development model and then hiring marketing to create demand.