It's been a year since Google searches on mobile devices surpassed those on personal computers for the first time. Naturally, the company is adapting to change --- it is already prioritizing mobile-friendly sites in search results, it's done work in voice recognition, launched the AMP project for fast loading mobile web pages, it indexes apps and so on. According to a report by Search Engine Land, the next such effort will be creating a completely separate mobile index, which will eventually take priority over the original desktop one.
Google's trend analyst Gary Illyes announced the news at Pubcon, noting that the mobile index will be fully implemented "within months" --- though no specific timeline was given. Google will still have a desktop index, it just won't be as fresh as the mobile index.
It's unclear exactly how the mobile index will work. Search Engine Land argues that the mobile index may allow Google to use its ranking algorithm differently for mobile content, rather than relying on data from desktop content to rank mobile sites.
The news naturally raised some concerns that search results may end up being less comprehensive, as mobile sites often remove content and structured data to optimize for size. Google has yet to announce anything officially.
The move will increase the pressure on online publishers to make sure their sites are mobile friendly, and that their mobile and desktop sites show the same content to be properly indexed, though the writing has been on the wall for some time for non mobile-optimized sites.