Google recently posted a blog about mobile search rankings. While it has been rumored for a long time, Google finally made an announcement about it being a ranking signal.
Take away: Make sure your website is mobile friendly.
“Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices.”