Of Music, Payola and Disclosure

How do songs become popular? When and why do people pay for play? On July 26, I (virtually) sat down with Gabriel Rossman, a sociologist at the University of California, Los Angeles, and the author of the brilliant "Climbing the Charts," an analysis of radio airplay, and what it tells us about the diffusion of innovation. We spent an hour-and-a-half on instant messenger, hashing out what we know -- and what we don't -- about the way songs climb the charts, and what that might tell us about insider trading and supermarket samples. The resulting interview was lightly edited for readability, and is now presented here for your reading pleasure.

Megan McArdle: Start out by telling me about yourself, and how you got interested in the music industry.