Basically you can create a mobile ready version of your site or have your site redesigned to cater for mobile devices. In a mobile site, the basic content remains the same but the layout and structure are rearranged in a way that makes it easier for the user to navigate through when viewing it through a smartphone or tablet.
The end result is that the design elements and content areas in your site are not crammed into each other but rendered fast, beautifully and accessible. This will enhance the end user experience by ten folds.
What’s best is that you don’t need to have one website for desktop viewers and one for mobile. A mobile site can be seen in its full layout in a desktop but when viewed through any mobile device it will automatically adapt to be seen optimally. This will avoid users leaving the site simply because it is getting on their nerves.