Google’s built-in ad blocker for Chrome will go live tomorrow (15 February) and the company has provided more details about what we can expect from the filter.

The ad blocker, which was first announced back in June 2017, won’t work like traditional ad blockers and block all ads from appearing. Instead, the blocker will act as more of a filter and only stop ads that don’t meet the standards laid out by the Coalition for Better Ads.

In a post to the Chromium blog, Google says that it will evaluate sites using sample pages, and make a judgement on whether the site adheres to the standards outlined. Sites that are all clear gain a ‘passing’ grade, while those in violation will gain a ‘warning’ grade and those found to be consistently in breach will be evaluated as ‘failing’.

If a user visits a page that belongs to a site that Google deems to be failing, network requests will be checked against a list of known ad-related URL patterns. If a match is found in cross-checking, Chrome will block the request and prevent the ad from being displayed on the page.

Despite the block, Google will ask the user if they actually wanted to see the ad. On mobile, a notification will appear in an infobar at the bottom of the screen, while desktop users will get a message indicating that a block has occurred along with the option to disable the setting.