Team Fortress 2.
Valve introduced the Mann Co. Store to the game at the end of September, which was a platform that enabled player-to-player trading and provided a storefront for modders to sell their custom content, and kept 25% of profits.
Some of the royalty figures were so high however that they exceeded PayPal deposit restrictions, so Valve flew the highest earners - Spencer Kern and Steven Skidmore - to its door to hand the cheques over in person.
"It was completely mind-blowing, the size of the return that we're getting on these things," Kern told .
Valve President Gabe Newell hopes this is a business model that will catch on.
"It benefits us because it grows the community, right? These (content creators) benefit, but we benefit too," he reasoned.
"Team Fortress 2 is a better product because we have community contributions in it. They're going to go off and listen to what the community says about how they can do that better, and we can draft along, as we both benefit."
"Once people ... realise this is about their community, and that the right people are getting the benefits, ... after a while, they'll say, 'This is really how these kinds of communities need to work.'"