Here’s another case for using Responsive Design. Your separate mobile site may be hurting your search rankings. This article SEO for the mobile web on Web Designer Depot states that duplicate content between the desktop and mobile sites may draw penalties from search engines and separate domains may split the page’s link equity and decrease page rankings. Using responsive design is the best solution to avoid duplicate content. The same content can be formatted to fit the view-port of any device that browses it be it a mobile phone, tablet or desktop computer.