In an announcement by Google, it began the process of rolling out the mobile-first index to more sites. According to the search engine, the rollout is only for those sites “follow the best practices for mobile-first indexing.”
This marks the first time that Google confirmed that it is moving a large number of sites to this mobile-first indexing process. Last October, Google said that a limited number of sites that had been moved over. In current situation, it appears that the process of mobile-first indexing on a larger scale has begun.
According to Google, it will notify webmasters/site owners that their sites are migrated to the mobile-first indexing process via messages in the Google Search Console.
The notification says as follows:
Google also said “site owners will see significantly increased crawl rate from the Smartphone Googlebot. Additionally, Google will show the mobile version of pages in Search results and Google cached pages.”
So what is mobile-first indexing? To Google, it is about how Google crawls your site. Google will have one single index, but how Google crawls and creates the index will be based on a mobile-first experience from here on out.
Google said:
To recap, our crawling, indexing, and ranking systems have typically used the desktop version of a page’s content, which may cause issues for mobile searchers when that version is vastly different from the mobile version. Mobile-first indexing means that we’ll use the mobile version of the page for indexing and ranking, to better help our — primarily mobile — users find what they’re looking for.
Google has a detailed developer document on mobile-first indexing. Also make sure to check out our FAQs on mobile-first indexing.