For some time Google have indicated in their mobile search results those sites that are mobile friendly and in April 2015 they started to roll-out a new algorithm that rewards websites that are 'mobile friendly', clearly indicating how important mobile search is to their users.
A responsive website is one that changes appearance based on the device window it is being viewed through, with the look of the site optimised for the window size therefore delivering the best mobile experience to the user. When you open a responsive site in a desktop browser and reduce the window down you will see it flow depending on the window size.
When we build responsive websites we create up to twenty different states, it really doesn't matter what the users screen size is, they will get the optimum experience. We build all websites mobile-first, this means that when coding we start at the mobile size and work up to ensure the loading speeds and user experience are prioritised.
Each year mobile traffic increases and websites that don't deliver the best experience to mobile users will suffer.Check your website now!