The mobile first index is one of the updates to Google’s ranking algorithm designed to make web browsing more enjoyable for people using mobile devices. The change means that the search engine, when determining the position of individual pages, takes into account not only how they look in the version for computers, but also whether they are adapted to small screens.
Such actions by Google are a response to the tastes and preferences of modern Internet users, who increasingly browse the web using smartphones and tablets. Changes to the algorithm were announced several years ago and have been gradually implemented since then. Therefore, having a website that looks and functions well on any device is an absolute must.