Steam

Steam is a digital distribution, digital rights management, multiplayer, and communications platform developed by Valve Corporation. It is used to distribute games and related media online, from small independent developers to larger software houses. In October 2012, Valve expanded the service to include non-gaming software. Steam provides the user with installation and automatic management of software across multiple computers, as well as 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), Steamworks, that developers can take advantage of to integrate many of Steam's functions within their software products, including copy protection, networking and matchmaking, in-game achievements and micro-transactions, and support for user-created content through Steam Workshop.

Though initially developed for use on Microsoft Windows, the client has expanded to include OS X and Linux versions, and clients with limited functionality on the PlayStation 3 console and for both iOS and Android mobile devices. In addition to being a central hub for gaming software, Valve has created a version of Steam with altered functionality to be used in schools for educational software, including a modified version of Portal 2 for teaching science and critical thinking lessons. Valve has also built SteamOS, a freely-available Linux-based operating system build around the Steam client, designed for its line of Steam Machine microconsoles as well as any personal computer meeting minimum specifications.

, there are over 3000 games available through Steam, and over 75 million Steam accounts. In December 2013, Steam surpassed over 7.1 million concurrent players. In October 2013, it was estimated that 75% of purchased games downloaded for the PC are through Steam.