What does this mean? Google wants your website to do more than simply look nice on a mobile device. Google wants it to function in the best possible way for the visitor on each device.
"A website changes and functions differently depending on the device it is being viewed on. It means your site will display differently when viewed on a desktop computer, a tablet, or a smartphone. More importantly, your visitors will have a user experience designed specifically for the device they are on when viewing your website. When properly strategized, not only will your ranking remain in place and improve, but your conversions will increase too. Google’s new mobile ranking algorithm will act like a ‘responsive report card’ and will include mobile-friendly usability and mobile app indexing.
Google will label mobile-friendly websites
This label will be visible in mobile search results
Google will use this when factoring your ranking
This will have a significant impact in search engine results"