I mentioned on Twitter that Google is going to roll-out mobile-friendly tags in Google search in mobile site.
Twitter to roll out mobile-friendly tag in search engines to indicate mobile friendly sites. http://t.co/vMSU3WQtF9
— Mohammad Hamza (@hamzadhamiya) November 18, 2014
The above image shows the mobile friendly tag. Test your site using Google Web Masters Mobile-Friendly Test tool.
So what's really Google demands? In fact, this is something a mobile user wants while browsing a site. A site that is recommend by Google have no software that is not common in mobile devices,like flash. Beside mobile Flash is an out dated solution to for many problems.
Next, Google wants site have font size enough to be readable without zooming, actually zooming creates horizontal overflow which makes the content scrollable, which counts in don'ts of responsive design. In a nutshell, making the site responsive is to make the layout flexible according to width of device.
|Screenshot for visible font-size without zoom|
Further Google bots looks at links on site, are they far enough to be clicked without zooming. Few links are present is a manner that could create problems. First includes the navigation bar links, if they are not far enough, the best option is to change it into drop-down. Next, footer have a bunch of links one by one, make the line height, padding or margin enough that your client won't get angry.
To get more feedback about Google mobile usability, Google Web-masters have tool that give feed back on mobile errors. To learn more about Responsive Web you can read my posts on responsive design.