This document defines growth hacking as a marketing technique used by startups that involves creativity, data analysis, and social metrics to gain exposure and sell products. It discusses how growth hackers think like startups by using a lean, experimental approach focused on customer growth. Growth hackers listen to customers through social media and analytics to understand their needs and influences, then refine their messaging and products based on data to create loyal, evangelistic fans. Examples like Uber, Airbnb, Hotmail and Dropbox are provided that leveraged growth hacking techniques like emotional storytelling, referrals, and addressing customer pain points.