Throughout the course of last year, Google made a bunch of moves showing that it was focusing on improving the mobile search experience for its users by way of getting websites (otherwise known as search results) to make themselves more mobile-friendly.

In November, Google added a “mobile-friendly” label to mobile search results for sites that deserve such a title. It also said it was experimenting with using the same criteria that would earn a site the label for a ranking signal to give mobile-friendly sites even more love in the search results.

Are you concerned about Google’s potential mobile-friendly ranking signal? Is this a positive step for Google? Let us know what you think in the comments.

Now, webmasters are getting warnings from Google when their sites aren’t mobile-friendly, which may suggest that Google is about to implement that ranking signal. According to Barry Schwartz at Search Engine Roundtable, who says several of his clients received the warning over the weekend, these are being sent out at mass scale by way of email and Webmaster Tools.

Schwartz shows a screenshot of one of the warnings, which says, “Fix mobile usability issues found on http://www…..” and then:

Google systems have tested 3,670 pages from your site and found that 100% of them have critical mobile usability errors. The errors on these 3,670 pages severely affect how mobile users are able to experience your website. These pages will not be seen as mobile-friendly by Google Search, and will therefore be displayed and ranked appropriately for smartphone users.

The message goes on to tell the webmaster to find problematic pages, learn about mobile-friendly design, and fix the mobile usability issues on the site. There is a link to view a report on the non-mobile-friendly pages, as well as one point to Google’s mobile-friendly guidelines. It also has links to a guide to making a CMS mobile-friendly, a page on Google’s Developer site about building mobile-friendly sites, and the Webmaster Central Forum, where webmasters are encouraged to ask more questions.

Here’s another of the messages Martin Oxby shared on Twitter:

Schwartz says Google had previously only notified sites that were “supposedly mobile friendly” when they had usability issues, but now they’re targeting sites that just aren’t at all mobile-friendly.

The mobile-friendly labels should be fully rolled out on a global basis by now. In mid-November, Google said it was rolling it out over the next few weeks. When the company made the announcement, it also laid out some criteria for earning the label as detected by Googlebot.

For one, a site should avoid software that isn’t common on mobile devices. It specifically mentioned Flash as an example. This actually follows Google’s previous shaming of Flash sites in mobile search results. Last summer, Google started showing messages for results that may not work in mobile results, such as “Uses Flash. May not work on your device.”

Google says sites should use text that is readable without zooming, and should size content to the screen so that users don’t have to scroll horizontally or zoom. Links should also be placed far enough apart so that the correct one can be tapped easily.

Google has a Mobile-Friendly Test tool here, which webmasters should find particularly helpful. You can simply enter a URL, and Google will analyze it and report if it has a mobile-friendly design.

If a URL passes the test, it will tell you that the page is mobile-friendly, and give you some additional resources, including information about how Googlebot sees the page.

If the URL fails the test, you’ll get reasons why the page isn’t mobile-friendly, as well as info about how Googlebot sees it, and resources to help you fix issues.

After Google gave the news about using mobile-freindly as a ranking signal in November, the company said it would continue to use desktop signals for ranking mobile results. Google’s John Mueller said this in a Webmaster Central mobile office hours hangout:

We need to focus on the desktop page for the search results for the most part. That’s also the one that you use with the rel canonical. As we pick up more information from mobile-friendly pages or from mobile pages in general, then I would expect that to flow into the rankings as well. So that’s something to keep in mind there.

I’d still make sure that your mobile friendly pages are as fast as possible, that they work really well on mobile devices, that you’re going past just essentially the required minimum that we had with the mobile friendly tool, and really providing a great experience on mobile. Because lots of people are using mobile to kind of make their decisions, to read content, and if your site is kind of minimally usable on mobile, but really a bad user experience, really, really slow, then that’s something that users will notice as well and they’ll jump off and do something else or go to a different site.

You can listen to him talk about that subject about 18 minutes and 50 seconds into the following video.

Google has been asking random mobile users to rate their search results based on a five-star rating system ranging from poor to excellent.

Last fall, Google Webmaster Tools added mobile usability tracking. This includes graphs that look at mobile issues over time, so you can see any progress you’ve made.

Muller had this to say when announcing that: “A mobile-friendly site is one that you can easily read & use on a smartphone, by only having to scroll up or down. Swiping left/right to search for content, zooming to read text and use UI elements, or not being able to see the content at all make a site harder to use for users on mobile phones. To help, the Mobile Usability reports show the following issues: Flash content, missing viewport (a critical meta-tag for mobile pages), tiny fonts, fixed-width viewports, content not sized to viewport, and clickable links/buttons too close to each other.”

“We strongly recommend you take a look at these issues in Webmaster Tools, and think about how they might be resolved; sometimes it’s just a matter of tweaking your site’s template!” he added.

Google continues to look for ways to improve Webmaster Tools as the nature of search results continues to shift. Last week, it launched a new structured data tool to help webmasters author and publish markup on their sites. The company says it will better reflect Google’s interpretation of your site.

Google is also asking webmasters for some ideas for new tools and features. The company wants to know what people want from it in 2015, and has a Google Moderator page where you can add your own suggestions or vote on others.

What would you like to see Google add to Webmaster Tools? Let us know in the comments.