Delta Air Line's In-flight Safety Video, and How Innovation Spreads

I'm flying from Boston to Atlanta on a 7:15 Delta flight, barely awake. We're just taking off. Right now people should be fidgeting or stealing a last-second peek at their phones. Instead, I notice people are looking at the seatback monitors and laughing. It's the in-flight safety video. The thing that you never, ever pay attention to is making people smile. This got me thinking about how innovation starts and spreads, particularly when it comes to advertising and communications. The short story...