Not only did Valve transform Steam from a glorified patch downloader to a premiere content delivery service, it now has 13 million users to boot. According to numbers released by Valve, 13 million active users now contribute to the "7 billion player minutes a month" gamed on Steam. This would never have been achieved had Valve not allowed companies such as PopCap Games, Capcom, and Eidos to distribute content through Steam. "Weve approached the development of Steam the same way we treat our online games; we release something weve tested, we internalize the feedback, and then we release new features and functionality based upon the feedback received. In Steams case, we have millions of customers who are gamers and dozens of customers who are developers and publishers," said Gabe Newell, president and co-founder of Valve.
News source: ExtremeTech