Mobile phones now have web browsers and are coming to your websites, but is the experience usable? Are they able to access the information you are sharing? Is the experience a good one or are they leaving in droves?
Mobile First responsive web design which has morphed into Responsive Web Design is the philosophy of taking the mobile browser experience as the first step in designing a website. Once you have met these needs you can build up to Tablet and Laptop screens very easily.
How does your site look on a smartphone? Have you looked?