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Mobile-only Indexing: From March 2021 Google Will Consider Only The Mobile

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Mobile-only Indexing: From March 2021 Google Will Consider Only The Mobile

Is some of the content on the pages of your site (articles, images, videos, meta title and meta description) only viewable from a desktop?

Are the pages of your site loading slowly from a smartphone and do not adapt to the screen resolution, forcing visitors to abandon them?

Has your mobile site been created on a specific subdomain (different from the desktop version)?

If you are in any of these situations, it is likely that your site is negatively affected by mobile-only indexing. In fact, with this update, Google's algorithms focus on pages and content that can be viewed from mobile to choose how to position your site in the SERP (Search Engine Results Page). Any gap from smartphones and tablets therefore risks a progressive decrease in organic ranking, i.e. natural search engine placement.

What are the guidelines to follow to avoid seeing all the efforts made so far in SEO in vain, thus losing visibility on search engines and new potential customers for your company? In this article we analyze together what mobile-only indexing will entail and what you can do, in practice and starting today, to optimize your site in this sense.

Mobile-only indexing

Cos'è la mobile-only indexing?

Mobile-only indexing 2

Mobile-only indexing is a further evolution of the update called "mobile-first indexing", implemented by Google since 2016. With this update, the search engine's crawlers (or spiders), i.e. the software responsible for SEO analysis and indexing of site pages, give top priority to mobile content. As a result, a site optimized for viewing on smartphones and tablets is more likely to reach the #1 position on the results page than a site optimized only for fixed devices.

What underlies this important update is the ever-increasing trend of browsing from smartphones. Suffice it to say, according to statistics reported by ahrefs.com dating back to June 2020, 52.2% of web traffic is via smartphone. This device is used not only to browse social networks, but also for active research by companies: 51% of those who use the Internet discover new products and services from their smartphones. Hence the need to propose, in the first page of the SERP, contents that are perfectly displayed from this device.

With mobile-only indexing, Google's spiders will focus almost exclusively on the mobile version of the site, which must therefore respond perfectly to the algorithms of the search engine. For this reason, content that today is only viewable from the desktop will probably no longer be indexed and positioned. In order to avoid losing ranking, it is therefore necessary to carry out an advanced SEO analysis, which will first identify all those contents that have the no-index tag from mobile and that, therefore, could not be visible to Google; secondly, the SEO audit will allow to adopt all those technical measures that will improve the performance of the site from mobile, meeting the approval of Google and the user.

Hai perso ranking a seguito dell'ultimo aggiornamento algoritmico di Google?  Parla con Mattia e fai analizzare il tuo sito!


All sites on the Web today will inevitably be affected by mobile-only indexing, which will change the organic positioning of pages in the SERPs for thousands and thousands of keywords. However, there is one category of sites that will be most affected: those that have a subdomain m. A trending practice a few years ago, in fact, involved creating a separate "section" of the site for mobile viewing. In many cases, a separate sub-domain was created, such as m.esempio.it (sub-domain of the main domain www.esempio.it), in which there were pages, news and all those contents intended for the audience that surfed from smartphones or tablets.

As specified on Twitter by John Mueller, Senior Webmaster Trends Analyst of Google, in cases like these, the search engine will not be able to visualize, and therefore index, the pages from desktop. The crawlers, in fact, will concentrate on the subdomain m., cancelling in fact the organic positioning acquired by the main domain (www.esempio.it). It is for this reason that, even when a user will use a fixed device to search on Google, he will be redirected to the m. subdomain.


Mobile-only indexing represents the culmination of a path that Google has been taking for a few years now: that of giving priority in the SERPs to all those sites that guarantee a brilliant User Experience not only on desktop, but also on mobile. We know, however, that mobile optimization is not the mere transposition of content on screens of different resolution, lower, but requires special precautions. Below we delve into the main aspects to be analyzed in our site and how to act to resolve any gaps or frictions.


With mobile-only indexing, the search engine will find the information and content of your site's pages almost exclusively from its mobile version. It is therefore essential that there are no impediments that could block the crawling of these elements to Google's crawlers. So check that the robots.txt file of your site, which tells spiders which pages to crawl and index, does not have any no-index or no-follow tags for the mobile version. In that case, the content affected by these tags would not be analyzed by the crawlers and therefore would not have the opportunity to acquire an organic ranking.

In addition to pages, it may happen that some essential elements in SEO, such as meta title and meta description, are set only for the desktop version. In this case, it is a good idea to insert the meta tags in the pages viewed from mobile: they will not only facilitate the recognition of the keyword for which you want to position yourself, but also gain more credibility and arouse user interest.

Mobile-only indexing refers not only to textual content, but also to multimedia content: images and videos are an integral part of the process of acquiring search engine rankings. It can sometimes happen to have many images to show to the user. In these cases, it is usual to adopt a particular technique. If, for example, there are 20 images to display, they are shown and scrolled without problems from desktop; from mobile, instead, it is preferred to show only some of them (for example, 3) from the beginning and allow the user to click on a button or a link to display the remaining 17. In this way, the page is graphically lighter.

mobile-only indexing 4Image taken from www.developers.google.com

Although the basic concept may seem correct, it is Google itself that suggests not to adopt this technique: in fact, Googlebots are not able to better understand user interactions and, therefore, to identify the "hidden content" within the page. As a result, it will be difficult for images that are only displayed by clicking on the button to be indexed by the search engine.

Hai perso ranking a seguito dell'ultimo aggiornamento algoritmico di Google?  Parla con Mattia e fai analizzare il tuo sito!

Is your site particularly slow in loading content from mobile?

Mobile-only indexing 5

Thanks to Pagespeed Insights, a tool made available for free by Google, we can check the level of SEO optimization and loading speed of our site, both from desktop and mobile. In order to improve this last aspect, it is necessary first of all to act on the multimedia content: before inserting images, it is good to lighten their weight. This can be done with graphics software, such as Photoshop, or with tools available on the Web: Jpeg Mini, TinyJPG and Lunapic are among the most popular online programs for compressing photos that are uploaded to sites.

The presence of an excessive number of redirects can also negatively affect page loading. This feature is generally adopted when you want to "forward" the user to a different resource (page, article,...) than the one he is looking for. However, every time a customer wants to approach a page subordinate to redirect, the serveur employs more time in order to show it: at first it passes for the eliminated and replaced page and, subsequently, redirects the customer to the page that is wanted to show. For this reason, it is good to use redirects when they are really necessary, like to avoid the presence of 404 errors, thus avoiding abusing them.

The excessive presence of plugins can also cause annoying slowdowns. If you have installed plugins that you are not currently using from mobile, proceed to uninstall them to lighten the portal.

Once you've implemented all these changes, your loading speed should already be greatly improved. If not, it is likely that the negative performance of your site comes from an outdated and underperforming hosting: so consider upgrading or choosing a new provider.

Is the mobile display of your site's pages good?

mobile-only indexing 6

Paying attention to how pages are viewed from smartphones is crucial: if a user can't read the textual content because it's too small or is forced to zoom in and out of images to view it, they could easily become impatient and head to other results. This means losing credibility not only in front of a visitor who could have been converted into a new business opportunity, but also in front of Google: the increase in the bounce rate (the percentage of users who visit a single page of the site and then abandon it permanently) acts as an alarm bell for the search engine algorithms!

Make sure that the visitor is never forced to scroll horizontally: the entire content must be present within the column of the smartphone screen and the scroll must be vertical only. In addition, make the font width higher than the screen of fixed devices: in this way, the user will not have to bring the smartphone closer to the eyes or zoom in to read clearly.

Always adopt a responsive design, which allows you to adapt your site content to multiple screen resolutions. Take into account the concept "less is more" to create a minimalist structure of your pages, which keeps them loading quickly and focuses the user's attention on the elements that are really important for your business. In this way, you will be sure that, from whatever device your visitor visits your pages, they will always see them flawlessly.

Need support in mobile optimization of your site?

Mobile-only indexing puts the mobile version of every site in Google's spotlight. It is therefore essential to optimize pages for mobile devices, such as smartphones and tablets, so that the search engine can scan them, index them and position them in the SERPs. In addition to the precautions described in the previous paragraphs, it is good to always consider the importance of implementing all the other, and more common, techniques for SEO optimization of the site (for example, the preliminary analysis of keywords, the inclusion of meta tags, the creation of alternative text in images, ...). By doing so, we won't have to fear algorithmic updates and we will be able to use mobile-only indexing to our advantage, outperforming online competitors and being found by new potential customers.

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Mattia Mella

SEO Expert - NetStrategy's SEO talent, Mattia graduated from the University of Verona and then immediately immersed himself in the world of algorithms and optimization, deepening his Search Engine Optimization skills in the field. Thanks to his analytical spirit and natural interest in the digital world, he joined our team and today, navigating from one keyword to another, Mattia is NetStrategy's SEO Expert.

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