Dan Goodin - ars technica




Google developers this week debuted a long-anticipated feature in Chrome that automatically blocks one of the Internet's biggest annoyances—intrusive ads.

Starting on Thursday, Chrome started filtering ads that fail to meet a set of criteria laid out by the Coalition for Better Ads, an industry group. The organization is made up of Google and others, and it aims to improve people's experiences with online ads. In a post published Wednesday, Chrome Engineering Manager Chris Bentzel said the filtering will focus on ad types that were ranked the most intrusive by 40,000 Internet uses who participated in a survey. On computers, the ads include those involving:

  • pop-ups
  • auto-playing videos with audio
  • "prestitials" that cover the screen that include a countdown timer
  • large images that stick to the bottom of a page, regardless of efforts to scroll

For mobile devices, intrusive ads include those with:

  • pop-ups
  • "prestitials" that appear on a page before content has loaded and block the content
  • densities of more than 30 percent of a page's height
  • animated images that rapidly flash or change background, text, or colors
  • video with auto-playing audio
  • "poststitials" with countdown timers appear after the user follows a link
  • full-screen images that appear on top of content and force user to scroll through
  • large images that stick to the side of a page, regardless of efforts to scroll



Bentzel said websites will be evaluated on the Better Ads Standards and assigned a status of passing, warning, or failing. The new Chrome ad filter first checks if the page being visited belongs to a site that received a failing grade. If it does, Chrome checks network requests for JavaScript and images against a list of known ad-related URL patterns. When there's a match, Chrome will block the request, preventing ads from displaying. The set of patterns is based on these public EasyList filter rules and includes patterns matching ad providers including the Google-owned AdSense and DoubleClick. Chrome will display a message indicating it is blocking ads and provide an option to allow ads to be displayed.

"It's important to note that some sites affected by this change may also contain Google ads," Chrome VP Rahul Roy-Chowdhury wrote in a separate blog post. "To us, your experience on the web is a higher priority than the money that these annoying ads may generate-even for us."