That figure represents items created for three of Valve's most popular games: Team Fortress 2, Dota 2 and Counter-Strike: Global Offensive. Valve claims the $57 million sum was split between 1,500 creators representing 75 different countries from around the globe. That works out to an average of $38,000 for each creator.
Alongside the financial milestone, Valve has announced plans to launch new curated Workshops for Dungeon Defenders: Eternity and Chivalry: Medieval Warfare, as well new Steam Marketplace analytics tools that should make buying and selling items both easier and more nuanced. For more, visit Steam.