On September 18, 2018, people started noticing a new notification in their Google Search Console accounts. Google was sending a message that announced “Mobile-first indexing enabled for [insert site name here].”

What is Mobile-First Indexing?

Mobile-first indexing essentially means that Googlebot will use the mobile version of a website to assess it for ranking on mobile devices. The change has occurred as previously, Google only used the desktop version of websites to determine their index on search engine result pages (SERP). This meant that mobile users may have had difficulties viewing certain websites that weren’t mobile-friendly, such as having to zoom-in on content or incurring lengthy load time.

The problem was that so many site experiences drastically differ from desktop to mobile. Since more and more people are searching on mobile, Google wants to reward the sites that deliver a stellar mobile experience. Hence, the mobile-first index. Now, Google will crawl and index the mobile version of a site.

With the rolling out of those messages, mobile-first is actually in effect for most sites as of September 2018. Hopefully, you’ve taken advantage of the time since Google first announced mobile-first to optimize your site’s mobile experience. If so, you shouldn’t see a huge wobble in performance.

However, if you notice changes in rankings or traffic in the past few weeks, it’s recommended that you investigate your site. Use Google’s very own Mobile-Friendly Test to see how it evaluates your site.