Responsive website design is not a new thing, back to 2012, Google strongly recommended the use of responsive web design and presently deems it to be the best practice for smart-phone optimized websites. It is a technique to build web pages that alter how they look using CSS3 media queries. That is, there is one HTML code for the page regardless of the device accessing it.
Responsive web design (RWD) is a web design approach aimed at crafting sites to provide an optimal viewing experience—easy reading and navigation with a minimum of re-sizing, panning, and scrolling—across a wide range of devices (from mobile phones to desktop computer monitors).
A site designed with RWD adapts the layout to the viewing environment by using fluid, proportion-based grids, flexible images and CSS3 media queries, an extension of the @media rule. – Wikipedia
In the other words, responsive design website will automatically fit any screen size you are using, whether it is desktop, mobile or tablet. This will help you keep your brand strong across any screen your visitor uses, your logo, colors and design will still be present.
The result of responsive design website displayed on the screen is different as the site that use a mobile plugin, which will mainly look like a generic RSS feed with or without your logo.
With a responsive website, Google can easily crawl and index your website content. Just for this reason alone, if you haven’t do it, you should get a responsive design site for your business!
Beside above, here are the top 5 reasons to use responsive website design