What is a mobile Friendly Website?
It is self-explanatory, i.e. simply a website that adapts itself when display on a hand-held device such as smartphone or tablet. The changes are not only aesthetics but also technical. A mobile friendly website is also better to use, it helps the information load faster and the emphasis is to make the reading experience easier; as a mobile phone's screen is 1/5th the size of an average desktop computer. The website should be easier to navigate and include highly visible menus that are easy to navigate and cannot include Flash as it is no longer supported by Apple products.
Why is IT important?
First of all it is important because you want your users to have a good experience instead of bad memories about their time on your website. Plus, you must not forget about the huge increase in traffic that a hand-held device can funnel into your website.
Last but not least, Google started penalising websites which don't display well on mobile. Google announced last year: “We will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results.”.
How Do I know if a website is a Mobile Friendly website or not?
Many solutions exist to know whether a website is a mobile friendly website or not. The easiest way might be to use the Mobile Friendly Test tool that Google Search Console offers you on https://search.google.com/search-console/mobile-friendly.
Alternatively you could check without any tools:
1. Open your website in a browser such as Chrome.
2. Resize the window by grabbing the window's edge with your mouse and drag it all the way to the opposite side until you can’t shrink your browser any further.
3. Analyse, if your website looks correct, like the one on the left, don't worry you have a Mobile Friendly Website. If not all of the website's content is immediately visible, like the one on the right, then you probably don't have a Mobile Friendly website and should start worrying about Google penalty.