This document discusses how YouTube and social media have altered content marketing and communications models. It provides background on traditional models like Lasswell's communication model from WWII and discusses how YouTube uses a two-step flow model. Case studies are presented on campaigns by Yell and Piper Aircraft that achieved success through YouTube and social media. The document advocates mapping influencer networks and finding influencers who are more likely to purchase. It also suggests marketers can learn from Amerigo Vespucci who helped discover that content and influence don't just revolve around the marketer, but that the marketer revolves around influential content and audiences.