Desktop Sites are not mobile-friendly when viewed from the Mobile devices. Mobile Sites need to provide users precisely what they are looking for quickly and simply. There are four times as many mobile devices than desktop computers.
A staggering 2 billion people worldwide have a mobile device. A majority of searches are now coming from these devices. Mobile friendly sites can boost site SEO and overall user experience.
I have built a demo site that uses common CMS for Mobile and Desktop site.