Your new company went online yesterday, and you have a marketing budget of zero. How are you supposed to create a movement around your product? How can you reach your first thousand or million customers? Starting from scratch feels impossible. This is where growth hackers come into play. You may have never heard of growth hacking, but you have certainly used the billion-dollar brands that emerged from it: Hotmail, Airbnb, Facebook, Dropbox, and many others. Growth hackers thrive on doing what traditional business people consider impossible: creating something out of nothing. They "hack" their company's growth to create a narrative of sensational success that turns enthusiastic media, users, and social networks into a viral marketing force, enabling exponential growth for their business. Silicon Valley has recognized that growth hacking—not TV advertising and billboards—is the secret to successful startups.