So logging in to webmaster tools following an email from Google about Mobile-First Indexing on one of our sites, we found the following documentation.

Mobile-first indexing enabled for https://mysite.com/
May 17, 2018

To owner of https://mysite.com/,

This means that you may see more traffic in your logs from Googlebot Smartphone. You may also see that snippets in Google Search results are now generated from the mobile version of your content.

Background: Mobile-first indexing means that Googlebot will now use the mobile version of your site for indexing and ranking, to better help our (primarily mobile) users find what they’re looking for. Google’s crawling, indexing, and ranking systems have historically used the desktop version of your site’s content, which can cause issues for mobile searchers when the desktop version differs from the mobile version. Our analysis indicates that the mobile and desktop versions of your site are comparable.
For more information:
• Monitor your index coverage using the Index Status report.
• Monitor your impressions, clicks, and site appearance using the Performance report.
• If you have any additional questions, drop by our Webmaster forum for more help – mention message type [WNC-20058194] or our public events.

It is VERY important to note that this took more than a year to happen since the site was updated to a responsive template.

Some of the language in the documentation I find interesting: “You may also see that snippets in Google Search results are now generated from the mobile version of your content” and “Our analysis indicates that the mobile and desktop versions of your site are comparable”.

Google Search results are now generated from the mobile version of your content: This is of no concern to me as the content displayed between the versions is near exact, but what if it wasn’t? What if the mobile version was lean on content…. That could be a big problem. What if your mobile version is a separate version all together? Worse, what if people start landing on your mobile site by default and are not properly redirected (this is a problem I have noticed with browser intricacies)? I think if I had a mobile cart instead of a responsive site this would move me to get responsive! The documentation is here.

Google says: “If you have a site configuration where the primary content and markup is different across mobile and desktop, you should consider making some changes to your site.” (BINGO)

Google Also says: “If you are a site owner who has only verified their desktop site in Search Console, please add and verify your mobile version.” (I would be looking to go responsive instead)

And: “Your mobile site should contain the same content as your desktop site. If your mobile site has less content than your desktop site, you should consider updating your mobile site so that its primary content is equivalent with your desktop site. This includes text, images (with alt-attributes), and videos – in the usual crawlable and indexable formats.”

Our analysis indicates that the mobile and desktop versions of your site are comparable: Geee, great. So a robot using a mathematical algorithm decided this? I find that concerning. Also, what happens if Google didn’t find the version “comparable”?

In reality, we already know Google and other search engines are favoring mobile ready sites with more favorable rankings, but in beginning in July 2018 Google will begin (take this with a