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Google’s Mobile-First Index: What Do We Know So Far?5 min read

5 min read

Google announced on Friday that they are launching a test of their “mobile-first” index.

Quite what that will mean in praxis is slightly opaque (for Google too – they have repeatedly called this “an experiment”), but the reasons for doing it are transparent.

Mobile traffic continues to grow, but Google still uses Desktop pages to rank results. This latest move will see Google use Mobile pages to evaluate relevance to a search query which, in theory, should deliver better results to an increasingly Mobile user base.


Although much is still up in the air, we have collated below everything we know to date.

What Exactly Will Happen?

The aim is for Google to use Mobile sites as the basis for their index, rather than their Desktop counterparts. This means that Google will continuously crawl Mobile sites and index their content; when a search query is entered, Google will dip into this content inventory to judge which results to serve and in which order.

So, it is really worth revisiting your Mobile site before this change does occur. If your Mobile experience is significantly slower or thinner than Desktop, this may be reflected in your rankings!


Google are aiming for a “quality-neutral” impact (ie. no drastic changes), but this will depend on the disparity between the Mobile/Desktop sites that are crawled. The aim is to roll this out globally, to all users, within the next year once Google are happy with the results.

Why Are Google Choosing to Do This Now?

The mantra “mobile first” is an easy catch-all term, but its application is valid in many cases. We have had numerous warnings (the ‘mobile-friendly’ tag, for example) about this shift in focus for Google, and there are probably as many stats about the growth of mobile as there are mobile users now.

And for good reason – the numbers paint a very clear picture:


Beneath this surface lies a much more fractious landscape across verticals, countries and demographics, but the overall trend can’t be denied.

Mobile isn’t necessarily taking desktop’s share of the pie across the board, but the pie is getting bigger:


Therefore, this is not a change intended to damage the Desktop experience; it is simply a reflection of an ecosystem where Mobile (particularly in emerging markets) increasingly takes precedence for most users. As such, it makes sense that Mobile sites should be the first port of call when assessing content.

What Will Happen to the Desktop Index?

Google has stated that they do not expect to maintain separate indices for Desktop and Mobile results. However, they have not ruled this out as part of future experiments – they know what outcome they want to achieve and will tweak things as required to get there.


The most likely way of achieving this, however, is that there will be one index, which will crawl Mobile pages as its jumping off point rather than Desktop pages.

What if my Mobile Site has Less/Worse Content than Desktop?

This is the one area that could cause notable ranking fluctuations. For example, could sites that rank well based on their Desktop sites be hit with a Panda penalty based on their sub-par Mobile site content?


Google has been unequivocal on this front: no serious fluctuations are expected and they will test in a lot of detail before rolling out globally. Nonetheless, it is indicative of the level of machine learning incorporated within the algorithms now that no guarantees can be provided. If the ranking algorithms are taking the new, mobile-first index into account fully, it stands to reason that search results will reflect the quality of the content crawled.

Perhaps Google’s assertion is an overly optimistic assessment of the quality of Mobile sites; as a result, it’s really worth analyzing your content again to make sure this won’t have a negative impact. If your Desktop and Mobile versions are markedly different, there will most likely be some effect given that the competitive landscape will also have changed.


Will Content be Indexed Faster?

This could be part of a wider initiative to start indexing Mobile content much faster. This will be of particular pertinence to larger publishers, and could see Google start to take on Twitter for a different type of traffic – users looking for instantaneous information on the go about live events.

As yet, there have been no announcements on this front, but it wouldn’t be a surprising move given the recent elevation of AMP results.

What Will the Impact be for Businesses?

Google has made it clear that even if you don’t have a Mobile site, they will simply crawl your Desktop site for content – even if the user is on a mobile device.

The key thing for businesses will be to make sure they are abiding by all of Google’s best practices for Mobile site experience, paying a lot of attention to site speed.


Here are a few more handy tips for site owners taken from Google’s original post: If you are a site owner who has only verified their desktop site in Search Console, please add and verify your mobile version.

  • If you only have a desktop site, we’ll continue to index your desktop site just fine, even if we’re using a mobile user agent to view your site.
  • If you are building a mobile version of your site, keep in mind that a functional desktop-oriented site can be better than a broken or incomplete mobile version of the site. It’s better for you to build up your mobile site and launch it when ready.

Final Thoughts

From Google’s perspective, this is a move that is entirely in keeping with how its users search for and consume content now. Why evaluate Desktop pages to judge the quality of Mobile content?

Desktop/ Mobile

For users, the impact should be negligible at first, but this is potentially part of a wider move to create a searching experience that aligns with user behavior in 2017 and beyond.

For site owners, this shouldn’t change too much as the warning signs have appeared in abundance in the past 18 months. For those unable or unwilling to adopt this mobile-first approach, Google will still crawl and index the Desktop version as it has done up to now.

Whether there are plans at Google to use this index to deliver a fundamentally different search results page is unclear for now, but this is undoubtedly indicative of Google’s business priority for the foreseeable future.