Google is set to make more changes to its mobile search rankings, this time downranking websites with annoying, overly-large popups asking users to download their app. Called interstitials, the popups cover a significant portion of the webpage upon arrival, making for a generally poor user experience.

Starting today, Google is updating its mobile-friendly test page for webmasters to point out the issue on their websites. Starting November 1, Google will mark websites with obtrusive interstitials as non-mobile-friendly. From Google:

After November 1, mobile web pages that show an app install interstitial that hides a significant amount of content on the transition from the search result page will no longer be considered mobile-friendly. This does not affect other types of interstitials. As an alternative to app install interstitials, browsers provide ways to promote an app that are more user-friendly.

Those user-friendly app promotions that Google is referring to are app install banners that appear at the top of a mobile page — something you're probably familiar with from visiting Android Central's mobile site.

Source: Google