From the Google | Webmaster Central Blog:
Webmaster level: all
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. 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. Today, we’re announcing two important changes to help users discover more mobile-friendly content: