Google announced that after November 1, mobile web pages that show an app install interstitials will no longer be considered mobile-friendly. This will not have any affect on the other types of interstitials. As an alternative Google will offer a different form of app install banners.
A new study from Google has determined about interstitial advertisements, that those full-screen ads that cover the interface of a host application have the negative effect on the mobile user experience. So Google based on these results have decided to permanently retire the interstitials.
The banners that Google will use as an alternative will not obscure the content, yet offer the chance for users to either interact with them or close them down. This move follows a general trend of Google's increasing use of user experience (UX) factors when ranking web pages.Google Eliminates Interstitials in Mobile Apps!,