The roll-out of Google’s mobile-first indexing has led to some confusion and uncertainty among webmasters. Google yesterday issued a series of tweets aimed at clearing up common misconceptions around a number of issues.
URLs in search
If Google sees your site has different URLs for mobile and desktop, it will show the mobile URL to mobile users and the desktop URL to desktop users. The mobile version is the content indexed in both cases.
Crawled counts
The number of crawled counts generally won’t change but the balance will shift to mostly mobile. Google may temporarily crawl more when your site shifts over to mobile-first indexing.
Cached page
A bug means a cached page is not being shown for many mobile-first indexed sites. Google is working to fix this and it doesn’t impact on crawling, indexing or ranking.
Speed update
The speed update due in July, after which page speed will become a ranking factor in mobile search, is not related to mobile-first indexing.
Mobile User Interface
Google says hamburger and accordion structures are fine on mobile sites.
Requirements for mobile-first indexing
While confirming that mobile friendliness and a mobile responsive layout are not requirements for mobile-first indexing, Google says it’s about time to abandon desktop only and embrace mobile.
Ranking
Google confirms that being in the mobile-first index is not a ranking factor.
For more information and documentation on mobile and mobile-first indexing, see:
https://developers.google.com/search/mobile-sites/mobile-first-indexing
https://developers.google.com/search/mobile-sites/
https://webmasters.googleblog.com/2018/03/rolling-out-mobile-first-indexing.html