Means using the latest technologies to give a modern design that scales to work on all devices. Content on your website will automatically re-arrange to fit the device. Regardless of the device used to access your website, it can be read. Browsing the internet using tablet and phones is on the increase and Google is giving sites a higher ranking if they use responsive design technologies.
User experience (UX) is a significant part of any website. Being able to capture customers and keep them engaged with your content is important as the longer they are engaged the better the chance that they will do business with you. Google also measures engagement and if your site has low engagement then it can impact your search ranking.
In the past, if you wanted a good user interface for users of a phone, you had to create a separate mobile website with desktop directed to one and phones to the other, or you had to create an App. With the latest website development languages, they automatically present the content of your web page to show well on a phone or tablet. One site for all devices.
Internet statistics tell us that more than 60% of all people on the web are using mobile devices. So having a mobile capable website (responsive) is more important than ever.