In this episode of the Mobile Dev Memo podcast, I discuss the economics of advertising auctions with Garrett Johnson, who is a professor at the Questrom School of Business at Boston University. I find that the auction dynamic is one of the most poorly understood aspects of digital marketing for practitioners: most advertisers are so intently focused on their own business objectives that they ignore the machinations of ad platforms that are invisible to them. But the auction mechanic is the beating heart of digital advertising, and it determines the pricing that advertisers pay for ad inventory. I'm happy to record this foundational, evergreen episode because I think it might help to inform a broader discussion about pricing in digital advertising generally -- and to explain how it is that ad platforms don't set prices.