Ad tracking is like having a special spy who tells companies what you like and what you do on the internet. When you visit a website, click on a link, or use an app, this spy takes notes and sends them to the companies who want to sell you things.
The spy uses something called cookies, which are like little pieces of information that get stored on your computer or phone. And every time you do something online, the cookies add to your spy file.
The companies that get your spy file use it to know more about you. They figure out what ads to show you and what products to sell you. So, if you like dogs, you might see more ads for dog treats or toys.
But don't worry, you can tell your computer or phone to stop adding to your spy file. Just go to the settings and turn on something called "Do Not Track" or "Limit Ad Tracking." Then, your spy file will stay a secret between you and your spy, and companies won't know as much about you.