Today at SMX Advanced during the iSEO panel, Pierre Far, Google Webmaster Trends Analyst, announced clear guidelines and recommendations on mobile SEO. In short, Google recommends you go with a responsive design when possible, otherwise you can use device-specific HTML but Google asks you to take certain steps to communicate when you are using device-specific HTML.

Google has been known to offer contradictory advice on mobile SEO thus far and Google wanted to take a watch and listen approach to see how webmasters were implementing their mobile web sites. Now Google has come out with their official recommendations on how to build mobile web sites that work best for users and at the same time work well for Google.