OK kiddo, so you know when you watch videos or look at stuff online, sometimes there are ads that pop up and get in the way? Well, ad filtering is when you use special tools to block those ads from appearing on your screen.
It's kind of like putting on sunglasses to protect your eyes from the sun - you put on these tools to protect your computer or device from the ads that might be annoying or distracting.
Ad filters can work in different ways, but some of them use a special code to scan the webpage you're looking at and figure out which parts are ads. Then, they hide those parts from you so you don't have to see them!
Some people like using ad filters because it makes their internet experience faster and less cluttered. But other people think it's not fair to block ads because those ads might be how websites and creators make money.
Overall, ad filtering is a way to control what you see online and make your experience more enjoyable.