Google announced Wednesday that over half of the pages shown in search results globally are from Google indexing that content using mobile-first indexing procedure. That means that it is more likely that the pages you visit from a Google search are based on how Google crawled and indexed that content based on the mobile version of that page.
What is mobile-first indexing? Mobile-first indexing is simply how Google crawls and indexes the web. Instead of looking at the desktop version of the page, Google looks at the mobile version of the page. In more simple terms, Google is crawling and indexing your web page based on how it renders on a mobile phone versus a desktop computer.
Where can I learn more? We have many stories and articles about mobile-first indexing on this site. Here are some of the more important stories:
You can also learn more from this Google help document and more articles on this site.
More advice. Google will typically notify you when your site has moved to mobile-first indexing within Google Search Console. So make sure to check your messages in the Google Search Console. Google will also label your site as last crawled by the Googlebot smartphone useragent in the URL inspection tool as another signal that your site has moved over.
Google says you should pay attention to your structured data and alt-text for images on mobile pages with this change.
Why does it matter? If your desktop pages are different from your mobile pages both in terms of content and structured data, then your rankings may be impacted. Google has generally moved sites that have parity between mobile and desktop pages first to mobile-first indexing. But with over half of the search results now indexed through mobile-first indexing, it is just a matter of time until your web pages are moved over as well.