Pop-up ads are annoying on desktop, but even more frustrating on mobile devices when they sometimes take over the browser. Google wants to fix that: in a blog post, the company announced that, starting next year, websites with intrusive advertisements will be punished and may be pushed down in search results.
Essentially, Google wants search results to favor sites that have the best information and the least annoying advertisements that cover up that information. "While the underlying content is present on the page and available to be indexed by Google," the blog post says, "content may be visually obscured by an interstitial. This can frustrate users because they are unable to easily access the content that they were expecting when they tapped on the search result."
Google claims these intrusive ads and interstitials create "a poorer experience" for users, particularly on mobile where space is limited by smaller screens. It's not wrong—sometimes pop-up or pop-over ads that show up on mobile websites can take up the entire display, forcing you to view them while furiously trying to find the "X" to close them. After January 10, 2017, sites that show these kinds of ads (which include content-obscuring "please subscribe to our newsletter!" pop-overs) "may not rank as highly" in search results.