On November 4, 2016, the Google Webmaster Blog published an announcement regarding “Mobile-First Indexing.” This concept may sound a bit confusing, but simply put: Google plans to use mobile versions of pages as the basis for search rankings going forward—even when users search on a PC, rankings will be determined by mobile content, rather than primarily by the desktop version as was the case before. This is the exact opposite of what we previously understood about SEO.
In the past, the prevailing view in the industry was that mobile rankings were simply the result of making minor adjustments to PC rankings to account for mobile-specific factors. In other words, as long as your page ranked well on desktop and offered a decent mobile experience, your mobile search rankings would typically be just as good.
After the launch of mobile-first indexing, the logic was reversed: whether a site ranks well or poorly depends primarily on the quality of its mobile pages—including site architecture, page content, links, and loading speed—while desktop search simply takes “desktop-friendliness” into account on top of the mobile version. Google’s plan is to maintain a unified index, but the focus of the index has shifted from desktop pages to mobile pages.
The reason for Google’s adjustment is straightforward: mobile search volume has surpassed that of desktop. When search volume was dominated by desktop, rankings were naturally based on the quality of desktop pages; now that mobile search has become the mainstream, the ranking criteria have shifted toward mobile pages. In the past, when rankings were calculated entirely based on desktop pages, problems sometimes arose: for example, some websites created mobile versions that were simplified versions of their desktop sites—or even had completely unrelated content—to improve mobile loading speeds. If mobile rankings were based on desktop content, mobile users might not see the content they’re actually supposed to see—since the full content exists only on the desktop page. Of course, if a website doesn’t have a mobile version at all, rankings can only be determined based on the desktop version.
Google stated at the time that it would conduct small-scale tests over the next few months to evaluate the results and would roll out the update fully only after confirming that the user experience had indeed improved. Google engineers believed that the rankings of most websites would not change significantly, but they could not be entirely certain at the time.
For website owners, the conclusion is actually quite clear: if a website uses responsive design, there’s basically nothing that needs to be changed; if the mobile version uses a separate URL—especially if the content differs between the two versions—the content must be standardized as soon as possible. This approach is also worth preparing for in advance in China—if Baidu adopts a similar strategy in the future, many websites will have to make corresponding adjustments. Additionally, mobile pages typically have fewer links than their desktop counterparts, since few people build or edit content on mobile devices; as a result, the accumulation of backlinks and indexing may be compromised, which is another factor to consider.
