When a visitor opens your website on their mobile browser it will load a lot slower than a mobile friendly web design due to a full website's size and incompatibility with the mobile device. Users often also find it harder to navigate through a non-mobile friendly site compared to competitor's who have. Search engines like Google will also give you better ranking on mobile devices if you are mobile friendly.
Generally in business you want to be as accessible to your consumer's as possible. Having a mobile friendly site will make it easier for your client's to reach you. It is one of the most effective and convenient tools for marketing your business. As more people are using their phones to surf online, the better chance it is for you to expand your marketing reach and improve your online service.
by @masterofvectors
http://yourwebdesignjobs.blogspot.com/