Gabriel Rossman is a sociologist at UCLA. The author of Climbing the Charts: What Radio Airplay Tells Us about the Diffusion of Innovation, Rossman takes a deeply analytic toolkit to questions such as why 2005’s “My Humps” became a viral hit. The last 1/3rd of the podcast is devoted to discussing a recent paper that he is an author on, Network hubs cease to be influential in the presence of low levels of advertising. But first, we discuss other topics. Recently Rossman has been seeing a change in the intellectual and political climate in modern sociology, with a shift from the positive to the normative. We explore the disjunction between public perception of the field (very left-wing), and the reality of it (much more empirical and rigorous), and how the two are slowly converging. After a short digression on Napoleon Chagnon, I also asked him about how “knotty” our social networks are. How is it that some people seem to know many other people? Eventually, we do discussion advertising, influencers, and a reconsideration of Malcolm Gladwell’s The Tipping Point twenty years on.