For the first time, Google is looking at more than simply relevant content. The search-engine-in-chief is now also looking at how good of a user experience your site is providing to visitors and using this as a ranking factor.
"The recent change by Google will affect mobile searches in all languages worldwide and will have a significant impact in our search results.” - Google Webmaster Central Blog 2015
Should you update your website so that it is mobile ready?
A regular website is usually designed for viewing on a desktop computer. When viewed on a smaller mobile device, the user experience isn't that great as certain elements from the site might not appear or may not function optimally. Mobile-optimized sites solve this problem by creating a version of the website that specifically designed to look great on all mobile phones. In addition, mobile websites may also include features that take advantage of the advanced capabilities of a mobile phone such as a click-to-call button that, when clicked, places a call.
Mat Cutts of Google explains how this particular component of html script is no longer considered when search engines rank a page or post: