The Google ranking system which was based on the desktop version of page’s content to evaluate relevance to its users. Issues arise when the mobile page has lesser contents than the desktop page because the google algorithms do not evaluate the actual page that is accessed by a mobile searcher, thereby, giving the mobile user limited or broken or incomplete content but Google has realized most searches are made via mobile devices.
For a more effective result, Google has commenced experiments to make their index mobile-first. This does not change the fact that the search index will continue to be a single index of websites and apps, as a result of this, the Google algorithms will primarily use the mobile version of a site’s content to rank pages from the site, understand structured data, and showing snippets from the pages in the result. Google is out to build a great search experience for both the mobile and the desktop devices but it is important to note that search index will be built from mobile documents.
In the course of the mobile-focused index evolution, Google will continue its careful experiment over the nearest future on a small scale until they are confident enough that there is a great user experience on both fronts -Desktop and mobile- since it’s a new process, Google have readied a few help processes for webmasters and are:
– If you have a responsive site or a dynamic serving site where both the primary content and markup is equivalent across both the mobile and desktop (Geekoutput), nothing is expected to be changed.
– If you have a site configuration where the primary content and markup differs across mobile and desktop, then some changes should be considered on the site.
– A structured markup for both desktop and mobile versions should be ensured.
– The equivalence of structured markup across desktop and mobile can be verified by imputing the URLs of both mobile and desktop versions into the STRUCTURED DATA TESTING TOOL and compare the output.
– The addition of large amounts irrelevant markup to the information content of each document should be avoided when adding structured data to mobile sites.
– Use the Robots.txt testing tool to verify the accessibility of your mobile version to Googlebot.
– Sites do not need to make changes to their canonical links as these links will continuously be used as guides, serving the appropriate results to users searching on either version (mobile or desktop)
Source: Webmaster Central Blog