https://techcrunch.com/2018/02/14/how-chromes-built-in-ad-blocker-will-work-when-it-goes-live-tomorrow/

Chrome’s built-in ad blocker will go live tomorrow. It’s the first time Google will automatically block some ads in Chrome, but while quite a few online publishers are fretting about this move, as a regular user, you may not even notice it.

The most important thing to know is that this is not an alternative to AdBlock Plus or uBlock Origin. Instead, it’s Google’s effort to ban the most annoying ads from your browser. So it won’t block all ads — just those that don’t conform to the Coalition for Better Ads guidelines. When Google decides that a site hosts ads that go against these guidelines, it’ll block all ads on a given site — not just those annoying prestitials with a countdown or autoplaying video ads with sound.