If you've ever noticed those ads inside a mobile game, you have Zain Jaffer to thank. He co-founded Vungle and helped popularize rewarded video ads—the ones that revive your character or hand you in-app currency after you watch. 

In this Built to Sell Radio episode, Zain explains how he rode the smartphone wave to a $780M all-cash exit to Blackstone—and why he personally took home more than $100M. Then he gets candid about what came next.