Google has made its first official announcement regarding the rollout of mobile-first indexing.
To be sure, mobile-first indexing began prior to today’s announcement, this is just Google’s first real acknowledgement of it via its own channels. Representatives from Google have previously stated that a significant number of sites have already been migrated to mobile-first indexing.
Confirming what we’ve already known, Google has again stated it is only migrating individual sites that follow best practices for mobile-first indexing. Sites using responsive web design or dynamic serving are best suited for mobile-first indexing. When sites have AMP and non-AMP versions of content, Google will prefer to index mobile versions of the non-AMP page.
In an effort to deliver the best experience for searchers across all devices, mobile-first indexing means Googlebot will only crawl and index the mobile version of a page.
Since there are now more searches being conducted on mobile devices than desktop browsers, this is a way for Google to ensure the majority of users find content that’s optimized for their screen. If a site does not have a mobile-friendly version then Google will still crawl and index the site as-is.
To clarify, there is no ‘mobile-first index’ that is different from the main index. All content will live within the same index, but Google will now be using the mobile versions when available.
Rankings Will Not Be Affected
Google assures site owners that mobile-first indexing will not have an impact on rankings. This is simply a change to how content is gathered for Google’s index. In other words, a site that has been migrated to mobile-first indexing will not have an advantage over a site that has not yet been migrated.
However, mobile-friendly content will generally be ranked higher in search results when the user is searching on a mobile device. This is a measure that has been in place since 2015.
Google is Notifying Site Owners
Sites that have been migrated to mobile-first indexing are being notified via Search Console. In addition, site owners can expect to see significantly increased crawl rates from the Smartphone Googlebot.
Google’s Search Console notification will look similar to the example below: