The Google mobile first index is coming. It is not a question of if, more a question of when. According to snippets of information provided by Google employees, the current mobile index is a copy of the desktop version. The plan is to transition the mobile index to mobile only content and then start serving results from either based on the device. This is a great opportunity for webmasters. Here is a chance to build a content and user experience for the mobile devices.
Writing and designing for mobile devices is currently limited to responsive design. The same page is generated differently based on the resolution of the device. This is great when it comes to overcoming the smaller screen size. However, it does not take advantage of the unique properties of mobile devices. Apps already take advantage of these properties. The ability to have an exact location, type of phone etc. Now content needs to change.
Content should change according to the context. Let us look at an example of how sites can use mobile-first content to increase relevancy. The simplest example is shopping. When a user searches for a specific product and arrives at the website, the standard convention is to show the details of the product. In a mobile-first world, the page would give a short description of the product and then indicate where it can be acquired locally or nearby.