It's happened to all of us. You bring up a webpage on your mobile device, only to find out that a feature you were accustomed to using on desktop simply isn't available on mobile. While frustrating, it has always been a struggle for web developers and designers alike to simplify and condense their site on mobile screens without needing to strip features or content that would otherwise clutter a smaller viewport. The worst-case scenario for these trade-offs is that some features would be reserved for desktop environments, or perhaps a user might be able to opt out of the mobile view. Below is an example of how my personal blog displays the mobile version using a popular plugin by ElegantThemes[1] called HandHeld. As you can see, the vast page is heavily stripped down and is far easier to read... but at what cost? And at what cost to the link graph?
My personal blog drops 75 of the 87 links, and all of the external links, when the mobile version is accessed. So what happens when the mobile versions of sites become the primary way the web is accessed, at scale, by the bots which power major search engines?
Google's announcement to proceed with a mobile-first index raises new questions about how the link structure of the web as a whole might be influenced once these truncated web experiences become the first (and sometimes only) version of the web Googlebot encounters.
So, what's the big deal?
The concern, which no doubt Google engineers have studied internally, is that mobile websites often remove content and links in order to improve user experience on a smaller screen. This abbreviated content fundamentally alters the link structure which underlies one of the most important factors