Starting Jan. 10, 2017, Google will penalize websites that serve up intrusive interstitials, or pop-up ads, to users searching for content on mobile devices.
Websites and web pages that use such pop-ups will rank lower in Google's mobile search results after that date, the company announced this week.
The move is designed to make it easier for users to access mobile content, Google Product Manager Doantam Phan announced on the company's Webmaster Central Blog.
Although a majority of web pages have become more mobile-friendly in the past two years, the use of intrusive interstitials on pages that are displayed to mobile users has increased markedly, Phan said. While the underlying content itself is present on a page, pop-up ads often obscure the content and prevent users from accessing it easily.
"Pages that show intrusive interstitials provide a poorer experience to users than other pages where content is immediately accessible," Phan noted. This can be an issue, especially for mobile users because their screens are smaller.
Phan offered several examples of pop-up ads and interstitials that could put a website in danger of being penalized in Google's search results.
For instance, a pop-up advertisement that entirely covers the main content of a page when a user navigates to it from search results or when a user is looking at it will be considered intrusive.
Similarly, any pop-up that a user has to manually dismiss in order to access content will lower a website's ranking in mobile search.
Not all pop-ups and interstitials will be affected by the change. For example, websites can continue using pop-ups to inform users of their legal obligations, such as those pertaining to cookie use or those asking for age verification. Banners and interstitials that use a "reasonable amount" of screen space on a mobile device will also not be penalized.
According to Phan, the new measure is just one of several hundred that are used to rank pages on mobile search. Content quality and relevance will still play a large part in determining page ranking.
Google's move to penalize sites that serve up annoying pop-ups on mobile search content build on the company's efforts to get website owners, advertisers, content publishers and others to tweak their content so it is more mobile-friendly.
About two years ago, for instance, the company began affixing a mobile-friendly label in search results to distinguish content that it considered to be optimized for viewing on smartphones and tablets.
Among the measures it used to make that judgment were whether users had to zoom in or out or scroll sideways to view mobile content, the size and accessibility of links on a page, and whether the site uses features like Flash that are not common on mobile devices.
In the two years since Google began adding the mobile-friendly label, a majority of websites have made the needed changes, Phan said. Nearly 85 percent of all pages served up on mobile devices now meet Google's criteria for mobile-friendliness. As a result, Google will no longer use the label in mobile search results.