First off I know there is no 100% way to guarantee this. I'm just looking for the "most reliable", I suppose. We have had an issue where some people have opted to use our mobile site - it's faster, less ads etc. Another problem has been with the forums. Some links have pointed to the style assignment in vBulletin, which resulted in setting of a cookie for their style. Now when they go back, they only see the mobile version "by mistake". We need to automatically revert them back to the main style. My first thought is the user agent... should I just analyze this and if its FF/IE/Opera/Chrome/Safari then go to the non-mobile version? Any better solutions? Thanks!