From Google’s Official Webmaster Central Blog:
As more people use mobile devices to access the internet, our algorithms have to adapt to these usage patterns. In the past, we’ve made updates to ensure a site is configured properly and viewable on modern devices. We’ve made it easier for users to find mobile-friendly web pages and we’ve introduced App Indexing to surface useful content from apps.
More relevant app content in search results
Starting today, we will begin to use information from indexed apps as a factor in ranking for signed-in users who have the app installed. As a result, we may now surface content from indexed apps more prominently in search. To find out how to implement App Indexing, which allows us to surface this information in search results, have a look at our step-by-step guide on the developer site.