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Steam is a video game digital distribution/rights management, and social networking platform developed by Valve Corporation.
Development began sometime prior to 2002 under the codenames "Grid" and "Gazelle". It was first revealed on March 22, 2002 at the Game Developers Conference purely as a distribution network.
The beta client version was released in 2002 for users of the Counter-Strike 1.6 beta. It was mandatory to install and use the program for 1.6 beta users, although Steam was still optional. In 2004, WON was shut down and replaced by Steam.
When the release first opened to the public, users found the software to be buggy, chokes in connections to Steam servers, and inability to install the software.
In 2004, Half-Life 2 was released, requiring Steam activation to play.
On 12 September 2007, Valve released the Steam Community. It is a social networking service connecting players to each other.
On 26 April 2010, Valve released a major UI update to Steam. It is the largest update since the launch in 2003.
In 2014, Steam's logo and UI recieved another major change.
The Steam Market is a in-game item trading service provided by Valve, available to Steam users.
The Steam Workshop is a database for user-created content available to Steam users.
Steam Trading Cards
The Steam Trading Cards are virtual trading cards available to Steam games.