Steam is a video game digital distribution service and storefront developed by Valve Corporation. It was launched as a software client in September 2003 to provide game updates automatically for Valve's games, and expanded to distributing third-party titles in late 2005. Steam offers various features, like game server matchmaking with Valve Anti-Cheat measures, social networking, and game streaming services. Steam client's functions include game update automation, cloud storage for game progress, and community features such as direct messaging, in-game overlay functions and a virtual collectable marketplace. Steamworks, a freely available application programming interface (API) released in 2008, is used by developers to integrate Steam's functions, including digital rights management (DRM), into their game products. Many game publishers began distributing their titles on Steam that year. Initially developed for Microsoft Windows operating systems, Steam was released for macOS in 2010 and Linux in 2012. Mobile apps accessing online Steam features were first released for iOS and Android in 2012. The platform's storefront also offers other digital content and Valve gaming hardware, including productivity software, game soundtracks, videos and the virtual reality headset, Valve Index. The service is the largest digital distribution platform for PC games, with an estimated 75% of the market share in 2013 according to IHS Screen Digest. By 2017, game purchases through Steam totaled about US$4.3 billion, or at least 18% of global PC game sales according to Steam Spy. By 2021, the service had over 34,000 games with over 132 million monthly active users. Steam's success has led to the development of the Steam Machine gaming PCs in 2015, including the SteamOS operating system and Steam Controller; Steam Link devices for local game streaming; and in 2022, the handheld Steam Deck tailored for running Steam games. Source: Wikipedia (en)