Google believes you’d want to see more mobile-friendly websites when you do searches on a phone or tablet. So as of April 21, it will start giving websites with mobile versions higher placements on the results page, assuming you’re also using a mobile device.
Google’s will also start to use more information from indexed apps if you have them installed on your phone/tablet and (in case it needs log-in credentials to work) if you’re signed in. The company has long given ranking points to websites that are optimised for new computers and devices, and it also made finding mobile-friendly ones easier last year, so the change isn’t entirely surprising.
These changes are great news for mobile users as it should help motivate those sites that still don’t have a mobile site to actually build one. Google started highlighting mobile-friendly sites in results last year.
If you have a website and would like to know if Google recognizes its phone/tablet version you can test it with Google’s mobile-friendly test tool. Its worth doing especially since the company believes this change “will have a significant impact in [its] search results.”
Site admins who want to test their site’s mobile compatibility can use Google’s tools to quickly evaluate the status of a page.
Mobile Websites: Left: Responsive Right Dedicated/Stand Alone