This chapter identifies a duality between structure and agency in social media platforms in relation to the internet influencer phenomenon. Influencers navigate digital structures to build their online presence by creating sensationalist and engaging content that meets user demands. This cyclical relationship between influencers and social media platforms exemplifies how structures and practices are mutually reinforcing. Social media structures shape influencers, who in turn shape these structures through their actions and interactions with users. After identifying the top 25 most prominent general influencers in the U.S. along with the top 25 from the fitness and health industries, the chapter carries out case studies that reveal how adverse societal aspects of the influencer phenomenon can arise. In one case, a health influencer fabricated a story about curing terminal cancer with holistic remedies, while in another, an individual gained fame for his “primal” lifestyle and raw meat diet, but was later revealed to have used extreme anabolic and chemical enhancement. While not all influencers manipulate their audiences in such extreme ways, it is clear that the internet influencer phenomenon has significantly altered the social behaviors of millions of people.