Games are really part of a large economy. They are productivity platforms for goods and services.
That is Gabe Newell speaking at DICE Summit about reinventing gaming as we know it. In his 30 minute keynote he covered a variety of topics including innovating PC input, gaming in the living room, cloud gaming, and the essence of games.
Most coverage has been focused on the many preludes to Valve's SteamBox (or Steamcast if you will), but Valve's use of hardware is merely an extension of Steam into the living room. Their plans appear to be bigger.
Gabe's talk focused on a strong interest in building a self-sustaining economy within a platform (e.g Steam). One that provides value not only within the games but on the platform itself and distributes that amongst contributing users.
People spend huge amounts of time in these games... They work hard at it and they get better and they accumulate these goods and at the end of the day when they go to another game, all that's thrown away. It's like 'hey, you can buy a house and as soon as you move out of it, you get no money for it and we burn it down.'
In other words you are rewarded for the investment of your time with digital goods. These goods have no real world value and little functionality in games but because there is a functioning economy in play they can in fact attain value through trade, which can lead to real monetary value. It's creating value where there was none.
The idea of a virtual economy itself isn't new as it has seen great success through Second Life. However, it is striking idea for a platform, especially considering the locked-in nature of video games on a digital platform. We still can't sell or trade "used" games on Steam but you can trade that TF2 pimp hat.