Mobile-friendly websites will rank higher than non-mobile friendly websites in Google search result pages on mobile devices.
Starting April 21, Google will expand its use of “mobile-friendliness” as a ranking signal for mobile searches in all languages worldwide.
Along with mobile site getting higher ranking, starting Thursday, Google will start to use more information from indexed apps as a factor when ranking search results for users that are signed-in and have the app installed on their mobile devices, which means only Android apps today.
Apps that are indexed by Google through App Indexing will begin to rank better in mobile search.
Google said in their blog post;
When it comes to search on mobile devices, users should get the most relevant and timely results, no matter if the information lives on mobile-friendly web pages or apps. As more people use mobile devices to access the internet, our algorithms have to adapt to these usage patterns.
You may visit the Google Webmaster Central Blog for details about Google mobile-friendly search results.