There is no doubt online use by mobile devices is on the rise and will sooner rather than later be the way most people access the net. With that knowledge it should be abundantly clear to any business owner their website must be mobile friendly. The easiest path is to build a responsive site. This allow for access by many devices and yet can be managed through a single point. Building a separate mobile only site is certainly an option if you want something quick and easy but moving forward one must then manage two versions of the website and thus double the work when changes need to be made. However if you opt to go with a mobile version of your website here is good article on SEO best practices to help you increase your visibility online.