With the so-called "masking", you basically have ONE single page for each of your domains at GoDaddy. If you optimize the actual files of your websites, they will be shown as their real URL, probably something like whatever.com/folder. The only effort you can work on for your 3 domains is the minimal customization allowed by GoDaddy (if any) on those "masking" pages (I guess like titles and a couple of metatags).
Co-Founder@HostHideout. Profoundly influenced by #Bauhaus, @Nameslave unrepentantly embraces #Minimalism with a bias for functionality, color theory and pixel precision: a #multimedia messenger in the McLuhan sense. His totally irrelevant M.Ed. dissertation examines Organizational Culture and Change Management. He also likes Patrik Ervell, Wong Kar-wai and IKEA.