Like any other large-scale change to Google’s search infrastructure, Google’s decision to adopt mobile-first indexing has prompted a mixture of confusion, intrigue, and excitement.
This post will explain what mobile-first indexing is -- e.g., it is not two indexes running in parallel, it is a single index of desktop and mobile pages -- and how it affects you.
It will also look at what steps you can take to improve the experience for mobile visitors to your website and help you make important marketing and financial decisions on the relative importance of mobile and desktop traffic.
Before we do any of that though, let’s look at some hard data. It can be difficult in a world of proclamations about “the death of desktop” to gauge whether mobile traffic is important to your business and how important it is relative to desktop traffic.
Some of the Facts About Mobile Traffic
A search on Google for “desktop is dying” will return hundreds of authoritative results, a significant number of which have reached the same conclusion: desktop is in fact dying. Very few of these articles cite the statistics I am about to give you though.
- In Q4 of 2016, 22.7 percent of all e-commerce sales were generated on mobile however 76.9 percent of all e-commerce sales were generated on desktops.
- The average add-to-basket conversion rate for global desktop users is 3.63 percent while the average add-to-basket conversion rate for global mobile users is 1.25 percent.
It is evident that desktop isn’t dead – in fact, if you are a business owner who values transactions ahead of vanity metrics, then there is a likelihood desktop users are and will remain, your most valuable visitors.
Don’t let the disproportionately high amount of chatter about mobile distract you from the financial importance of desktop users.
Let’s look at some more mobile stats:
- Over 4 billion users worldwide now have access to the internet
- 52% of mobile traffic originates from a smartphone, and 43% originates from a desktop.
- In a number of developing countries, 1GB of mobile data still costs more than 20% of average monthly income. While data suggests more people have access to the internet than ever before, that doesn’t necessarily mean suggest active or regular usage.
- Google’s research has found that the average page load time on a mobile device is 22 seconds. Aberdeen Group has found a 1-second delay in page load can affect conversion rate by up to 7 percent.
This isn't to dismiss the importance of mobile; it will continue to have a significant impact on e-commerce. However, it is important to place its usage and uptake in the appropriate context.
What is mobile-first indexing?
Mobile-first indexing is as it sounds: Google will crawl and index mobile content first, and if no mobile version is available it will crawl and index the desktop version.
This is distinct from the historic approach of indexing desktop content for both mobile and desktop users. If a mobile version of a page is available, then the mobile version will be used to create search listings and determine visibility.
As Google is assigning rankings based on the mobile page, complications may emerge for webmasters offering a different experience between mobile and desktop websites which only display certain blocks of content to desktop users.
There has been some confusion around whether Google currently maintains one index for mobile pages and one index for desktop pages, i.e., two indexes. Danny Sullivan has, on the 14th March, unequivocally confirmed it does not.
Rather, it maintains a single index of mobile-first and desktop-first content mixed together — a single index of mobile and desktop content.
In another tweet on the 15th March, Danny Sullivan also stated that in the majority of cases Google currently indexes on a desktop-first basis, however moving forward most websites will be indexed on a mobile-first basis.
While there is no definitive time frame on when the majority of websites will be indexed on a mobile-first basis, it's evident that mobile is revolutionizing the way users access and interact with information online.
The emphasis placed on mobile may be disproportionate to its commercial impact. However, it is impossible to deny that mobile is vitally important for international targeting and that it is being prioritized by the world's largest technology firms (e.g., Google and Facebook, which account for 73 percent of all digital advertising spend in the U.S.).
For this reason, let's take a look at some of the steps you can take to prepare for mobile-first indexing and what you can do to improve the user experience for mobile users.
How to Create An Effective User-Experience for Mobile Users
Organizations take different approaches when it comes to serving content to mobile users:
- Responsive: the source code typically remains the same between desktop and mobile and the page scales dependent on the size of the viewport (the URL also remains the same). Responsive pages usually contain the meta viewport tag. If you maintain a responsive website, then you don’t need to make any technical changes for mobile-first indexing.
- Dynamic serving: while the URL remains the same, the HTML and CSS served will vary dependent on the device requesting the content; under this setup, Googlebot is less likely to recognize a different version of the page is available to mobile users. For this reason, Google recommends responding to requests with an HTTP Vary header to make this more apparent. You can read about Google’s recommendations here.
- Distinct mobile presence: the URLs are different for both desktop and mobile user-agents. This typically takes the form of a separate mobile website on a separate domain or subdomain, e.g., m.example.com.
It is important to remember Google sends a specific Googlebot to crawl mobile content. If the server responds with an HTTP Vary header, then it is a signal to Google that it should crawl the content with “Googlebot for smartphones.”
A responsive presence is the simplest of all of the configurations (and arguably the easiest to maintain). However, there is nothing yet to suggest Google will assign preference to one configuration over another.
Extra Implementation Steps For a Separate Mobile and Desktop Presence
If you maintain a separate presence for mobile and desktop visitors, then you will need to implement some technical changes if you haven’t done so already.
Within the desktop source code you will need to add the rel=alternate attribute to signify to the user-agent where your mobile content is hosted, and within the mobile source code, you will need to add the canonical attribute pointing to the desktop version.
The alternate attribute should also contain a CSS media query which signifies when a user-agent should use the alternate URL (this comes in the form of a maximum or minimum viewport width).
It is also vitally important to identify any discrepancies between your mobile and desktop website. For example, structured data, sitemaps, metadata, and search console tags should be present on both desktop and mobile versions of a page.
You can read more about configuration requirements for maintaining separate mobile and desktop websites at Google Developer.
Optional Mobile Optimization Tips
When it comes to improving the user experience for mobile visitors, the most important factor to address is page load time.While page speed is only a ranking factor for a small number of queries, it can become more of a factor if a website is prohibitively slow.
It is quite an old study – there have been hundreds of other studies which have reached the same conclusion since – however research from Amazon in 2008 found a 100ms delay in page load could affect sales by as much as 1%.
If you want to test your page load time, then try Pingdom’s website speed test tool. There are hundreds of methods to improve page load time however the most impactful in my experience is reducing image size.
On average, and according to HTTP Archive, images account for 51% of total page size. Choosing to compress images can have a significant impact on page load time and thus site-wide conversion rates.
Another option is Google’s Accelerated Mobile Pages (AMP). If you choose to utilize AMP, your pages will be served from a cache on Google’s servers and from a Google URL. AMP relies on a subset of HTML -- a heavily restricted subset -- and requires that you maintain separate AMP source code for all of your pages.
AMP has prompted a fair amount of criticism, notably in relation to ownership and monetization of content. However, a recent announcement suggests there are now over 31 million domains and over 5 billion pages relying on AMP (this is in contrast to 900,000 domains and 2 billion pages as of the middle of 2017).