Sean Ellis discusses growth hacking and how startups can take their business to the next level. He explains that growth hacking is not magic, but rather a rigorous process of experimentation involving generating ideas, prioritizing tests, running experiments, analyzing results, and optimizing what works best. Ellis provides examples of how companies like Dropbox, LinkedIn, and Airbnb grew through innovative experiments and by reverse engineering the growth strategies of successful startups. He emphasizes that growth requires testing many ideas, focusing on increasing user gratification, and relentlessly executing the growth hacking process.