Steam is not simply a program that gamers use to buy and play games on their computer. It is a program that features social functions on top of the gaming and the ability for gamers to make real money through the Steam Workshop.
The Steam Workshop launched in 2011 and offered a place where users could act as content creators for games developed by Valve and sell the content that they created on the Steam Market. Since its launch the Workshop has grown exponentially and has earned content creators quite a bit of money.
Items created by Steam users for Team Fortress 2, Dota 2, and Counter-Strike: Global Offensive have brought in over $57 million. That money was payed to over 1,500 contributors across 75 countries, but the best news has yet to come: The Steam Workshop is getting bigger.
The first curated Workshops for non-Valve games have opened: Dungeon Defenders: Eternity and Chivalry: Medieval Warfare. If this goes well, more curated Workshops for non-Valve games will be made available. This also means that there will be more content available for purchase to players.