We’ve all had the annoying experience of going to show a YouTube video in a classroom or to a friend only to have an advertisement play for five, ten, or thirty seconds before you can actually watch the video. How does YouTube know which ads to show to you? That’s partly based on your viewing habits and the channels to which you subscribe. It’s also partly based on what advertisers are willing to pay to appear on a video. That process happens in less than a second. Learn more about YouTube advertising and how much a video earns by watching the following CGP Grey video.

Applications for Education
Many students happily click from one video to the next (YouTube says that average user watches 40 minutes of video per day on a mobile phone) without thinking about the digital footprint that is left behind. Ask your students to think about the advertisements they see and how they get there. Then show them CGP Grey’s video. They might be surprised by what YouTube knows about them.

You can avoid much of the video viewing habits tracking by watching YouTube without signing into your Google account and by using an incognito browser window.