Google recently announced that it would be updating its search ranking signals to include mobile-friendly content. Users searching for content from a mobile device will soon see mobile-friendly content appear higher in the results returned from Google.
Mobile-friendly content includes a responsively designed website, or a site specifically built for a mobile device. This update should not affect searches made from non-mobile devices. The new updates will be put into place on April 21st.
For more information on this update, including steps you can take to get ready for this change, visit Google's Webmaster Central Blog: