Steam is a digital distribution service and storefront developed by Valve. It was launched as a software client in September 2003 to provide video game updates automatically for Valve's games and expanded to distributing third-party titles in late 2005. Steam offers various features, such as game server matchmaking with Valve Anti-Cheat (VAC) measures, social networking, and game streaming services. The Steam client functions include update maintenance, cloud storage, and community features such as direct messaging, an in-game overlay, discussion forums, and a virtual collectable marketplace. The storefront also offers productivity software, game soundtracks, videos, and sells hardware made by Valve, such as the Valve Index and the Steam Deck.