Go to www.netcraft.com, and in the upper left hand corner under "What's that site running", type in Valve's URLs.
Valve have generated billions of dollars and huge market share by running Linux on their servers. Yet, they have never raised a finger to help Linux, or acknowledge it for the success they have enjoyed due to it. (neither have any other companies that run Linux on their servers either, it's not just Valve by any means.) These companies would not be what they are today without Unix/Linux.
Unfortunate for these companies. Don't expect other people to do your work for you.