On April 21st 2015, an update at Google impacted most websites on the web. From April 21st 2015 onward, only mobile and responsive websites will appear in Google search results on mobile devices.
WHAT DOES THIS MEAN FOR ME?
To put it simply, if your website is not mobile friendly or responsive, your website will not show up in Google's search engine results on most mobile devices! You will become invisible.
WHAT DOES THIS GOOGLE UPDATE LOOK FOR?
The Googlebot must be allowed to scan your CSS and JS files in order to deem them as mobile friendly.
ANALYZE YOUR WEBSITE
The Google Chrome web browser provides an open source developer tool called, "Lighthouse" that you can use to see how your website is performing:
You can also see what your current website looks like on multiple mobile devices by visiting this site and entering your domain name: http://www.responsinator.com/
You can further have a look at the technology your site is running by visiting this site and entering your domain name: https://builtwith.com/
WHAT CAN I DO IF MY SITE DOES NOT PASS THE TEST?
There's no easy way to say this, but you have no choice except to upgrade your website to use a responsive or mobile friendly framework.
As always, if you are in need of assistance migrating your website or making it mobile friendly, we are here to help you. Contact us and we can help you stay visible to the search engines!
You can read the official announcement here: http://googlewebmastercentral.blogspot.fr/2015/02/finding-more-mobile-friendly-search.html