Wi-fi is now ubiquitous in most populated areas, and the way the devices communicate leaves a lot of 'digital exhaust'. Usually a computer will have a Wi-Fi device that’s configured to connect to a given network, but often these devices can be configured instead to pick up the background Wi-Fi chatter of surrounding devices. There are good reasons—and bad—for doing this. Just like taking apart equipment to understand how it works teaches us things, so being able to dissect and examine protocol traffic lets us learn about this.