You really have to be impressed with Valve's money-disappearing act...
It's interesting how psychology is often entirely dismissed as pseudoscience, quackery and whatnot. An argument could be made for the therapy side of things as there is a huge difference between what is taught at the university and what is done in practice. But cognitive psychology and neuroscience shouldn't be put on the same plate...
Valve is the only video game company (that I know of) that actively looks for psychologists (
http://www.valvesoftware.com/jobs/job_postings.html).
Under "duties" you can read the following: "Provide relevant insight into human behavior in order to shape gameplay and customer experience".
If you look at EA's, Activision's, etc. job offerings, the closest you get to a "psychologist position" are "UX designer" (related to cognitive sciences) and "Analytics" (experimental psychologists are trained to analyze huge sets of data). But none explicitly mention human behavior.
Regarding the Steam sale, I've never seen people being so openly manipulated (I'm referring to the groups) and being happy about it! I'm not criticizing, I just find it funny. I wonder how big Valve's death squad of psychologist/economists is, but it is sure worth every penny.