After well over a year of testing, Google is ready to shift some of its search engine foundations to focus on mobile. The company has started the rollout for "mobile-first" search indexing, which uses the phone-optimized versions of pages for indexing and ranking whenever possible. Searchers are "primarily mobile," Google noted, and this should give them a better chance of finding what they wanted.
The company is adamant that desktop-only sites won't vanish from the index, and that phone-optimized sites included in the first wave won't have an advantage over either desktop content or mobile pages that have yet to be included. And if it happens that a desktop site is more relevant to a given search, you'll still see it ranked higher than its mobile alternatives.
Even with all these conditions, there's no question that the tide has turned. Google had already emphasized mobile-friendly pages when searching on phones, but it's now using them as a reference point for the search engine itself. It's a not-so-subtle hint to site creators that they should fine-tune their pages for mobile if they want to stay in sync with Google's priorities.