Since launching Steam Workshop - Valve's community content marketplace - in 2011, over 1,500 creators have taken advantage of the service across 75 countries. More importantly, they've earned more than $57 million from selling in-game items for Team Fortress 2, Dota 2 and Counter-Strike: Global Offensive.

That works out to roughly $38,000 per person but remember, that's just an average. What's much more likely is that, like on YouTube, there are a few content creators making the majority of money and a ton of people that are earning very little.

In-game items up for sale include things like maps, new character skins, weapons, hats and taunts. It's items like these that help extend the life of a game.

Valve said that when they launched the Workshop, they expected that it would grow buy they didn't envision it happening this much and this fast.

Up to this point, however, the Workshop has been limited to games made by Valve. The company said that's due to the sheer number of challenges required in order to scale to a global audience of creators and players.

But now, after a ton of work, the first Workshops for non-Valve games have opened for Dungeon Defenders: Eternity and Chivalry: Medieval Warfare. Valve said it expects more curated Workshops to become available for creators and players in various games over the coming weeks and months.