Like you're on a new device or borrowing a computer, and you open a webpage - and literally every website blankets your screen with ads every-which-way and all kinds of permutations of springing up to try and get you to accidentally click on something. The actual news article or whatever is just an afterthought.
Literally - how the fuck do people use the internet without an adblocker.
pihole doesn't block YouTube ads, they're served from the same domain. still good as part of a multi-layered defense though