Google to Penalize Mobile Sites With Intrusive Pop-Ups Starting in January, some sites will be ranked lower in Google's mobile search results.

Google will rank mobile web sites that display annoying pop-up ads and other distractions lower in its search results starting early next year, the web giant announced today.

The move is intended to combat jarring experiences that sometimes force themselves upon users when they're navigating to a page on their phone or tablet that Google marks as "mobile-friendly." Those surprises include showing a popup that covers the main content of the page, displaying an alert bubble or other elements (called interstitials) that the user must dismiss and placing content "below the fold," requiring users to scroll down to see it.

"Pages that show intrusive interstitials provide a poorer experience to users than other pages where content is immediately accessible," Google product manager Doantam Phan wrote in a blog post. "This can be problematic on mobile devices where screens are often smaller. To improve the mobile search experience, after January 10, 2017, pages where content is not easily accessible to a user on the transition from the mobile search results may not rank as highly."

As part of the search algorithm changes, Google will also be retiring the mobile-friendly label. It says more than 85 percent of sites currently displayed in its mobile search results meet the mobile-friendly requirements. Sites that don't will be ranked lower in the results.

The changes could potentially affect a vast number of mainstream websites. Yelp, for instance, often shows a full-screen advertisement for its app on the mobile version of its website, requiring viewers to scroll down in order to read reviews.

January's changes won't penalize mobile pop-ups that Google determines to be unintrusive or provide a public service. Those include pop-ups advising users of a site's cookie policy, or age verification pop-ups for sites with objectionable content.