See the attached link. The Source engine will probably be ported on Linux, which means that there will most likely be a Linux version of Steam.
I have boycotted Steam because of the DRM it implements for now but if it is ever released for Linux I sure will buy Valve products. This will make Valve and Steam very popular in the "nerd" scene.
I hope StarDock will go a similar route and open up to multiple PC platforms instead of caging itself in by only developing games for windows. Your move