Steam is an Internet-based digital distribution platform developed by Valve Corporation offering digital rights management (DRM), multiplayer, and social networking. Steam provides the user with installation and automatic updating of games on multiple computers, and community features such as friends lists and groups, cloud saving, and in-game voice and chat functionality. The software provides a freely available application programming interface (API) called Steamworks, which developers can use to integrate many of Steam's functions, including networking and matchmaking, in-game achievements, micro-transactions, and support for user-created content through Steam Workshop, into their products.
Though initially developed for use on Microsoft Windows, versions for OS X and Linux operating systems, and a limited-function version for the PlayStation 3 console, have also been developed. Chatting and shopping applications for iOS and Android mobile devices have also been written. The Steam website also replicates much of the storefront and social network features of the stand-alone application. The success has led to the development of a line of Steam Machine micro-consoles and personal computers meeting minimum specifications, and SteamOS, a Linux-based operating system built around the Steam client.
As of February 2015, over 4,500 games are available through Steam, which has 125 million active users.Steam has had as many as 10 million concurrent users as of June 2015.In November 2009, Stardock estimated it at 70% and then later, in October 2013, it was estimated by Screen Digest that 75% of games bought online for the PC are downloaded through Steam.