For most of us, seeing an advertisement pop up while we’re scrolling on Instagram or reading an article or watching a video is the most banal experience possible. But in the background of those experiences is a $500 billion marketplace where our attention is being bought, packaged and sold at split-second speeds virtually every minute of every day. Online advertising is the economic engine of the internet, and that engine is fueled by our attention. Tim Hwang is the former global public policy lead for A.I. and machine learning at Google and the author of the book “Subprime Attention Crisis: Advertising and the Time Bomb at the Heart of the Internet.” Hwang’s central argument is that everything about the internet — from the emphasis data collection to the use of the “like” button to the fact that services like Google Search and Facebook are free — flows from its core business model. But that business model is also in crisis. The internet is degrading the very resource — our collective attention — on which its financial survival depends. The resulting “subprime attention crisis” threatens upend the internet as we know it. So this conversation is about the economic logic that undergirds our entire experience of the internet, and how that logic is constantly warping, manipulating and shaping the most important resource we have — our attention. But it’s also about whether a very different kind of internet — build on a very different economic logic — is possible. Mentioned: “Does Quora Really Have All the Answers?” by Gary Rivlin Google report: “5 Factors of Viewability” “Almost Impossible” Book Recommendations: Here Comes Everybody by Clay Shirky The Profiteers by Sally Denton Jim Ravel’s Theatrical Pickpocketing Thoughts? Guest suggestions? Email us at [email protected]. You can find transcripts (posted midday) and more episodes of “The Ezra Klein Show” at nytimes.com/ezra-klein-podcast, and you can find Ezra on Twitter @ezraklein. Book recommendations from all our guests are listed at https://www.nytimes.com/article/ezra-klein-show-book-recs. “The Ezra Klein Show” is produced by Emefa Agawu, Annie Galvin, Jeff Geld, Roge Karma and Kristin Lin. Fact-checking by Kate Sinclair. Mixing by Sonia Herrero. Original music by Isaac Jones. Audience strategy by Shannon Busta. The executive producer of New York Times Opinion Audio is Annie-Rose Strasser. Special thanks to Pat McCusker and Kristina Samulewski.