Google Search's migration to mobile-first indexing will soon expand to more websites across the web, Google stated in a blog post today. A limited experiment first began in late 2016, pushed by Google's goal to make search results more useful on mobile. Satisfied with the preliminary results, Google has now begun by migrating those websites that currently "follow the best practices for mobile-first indexing."
The switch to mobile-first indexing comes as the result of more and more people using a mobile device to browse — and search — the web. Traditionally, Google has used the desktop version of a page's content to index results in Google Search. When a site has different versions for desktop and mobile browsers — and in particular when the mobile version is an impoverished version of the desktop site — mobile users can often be led to a page with less or worse content than the search result would have had them believe. To address the issue, Google has been experimenting with 'mobile-first' indexing of results — that is, indexing a page based on the content a mobile user sees when visiting it.
Since the change is still rolling out gradually, site owners can choose to have their sites be part of the initial wave by simply ensuring they follow best practices, and Google will then notify them that their sites have migrated to mobile-first indexing through the Search Console. Apart from seeing an increased crawl rate from Google's smartphone webcrawler, owners will also find that the mobile version of their site will appear in Search results and in Google's cached pages.
Google is quick to note that there is no ranking advantage per se in a site being indexed in this new way: what changes is the way content is gathered, not how that content is ranked. Additionally, nothing changes for websites which only have a desktop version: since a user sees the same content regardless of their type of browser, indexing the desktop or 'mobile' version of the site is the same thing in practice. (Sites that do not have a mobile-friendly version are penalized in their ranking, but that has been in effect since 2015 and is unrelated to this change.)
Google will continue to collect feedback on the switch to mobile-first indexing and monitor how things develop. Hopefully, the change will be helpful in fixing the frustrating content discrepancy that can still be found between the mobile and desktop versions of some websites today.