Google recently announced: “Starting April 21, 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.”
In the last few years, as the use of mobile and tablets has grown, there has been an increased need for website designs to cater for these new mediums, which are different shapes and sizes to the traditional desktop screen.
Responsive Design is the term used to describe a website which shows different layouts depending on the device is it viewed through.
A Neon article a few years ago showed how responsive designs work.
You can check whether your website is going to be relegated by Google by testing is with their Mobile Friendly Test.
It will not be known until the 21st April 2015 what the impact of these changes will be. However with the mobile website visitors always on the increase, it is best practise to ensure your website has a mobile design to ensure the user experience is as positive as possible.
A mobile design can be retrospectively added to a website and there is no need to redesign the whole website.
Neon Web Design Poole have built many responsive designs (including this site) and are happy to go through the options with you.