Despite increased competition last year, Valve's digital distribution platform Steam managed to increase year-over-year unit sales by over 100 percent for the seventh straight year in 2011.
Steam grew sales for its 8-year-old PC games download service in the face of newly launched competitors from other major companies, such as Apple's Mac App Store and Electronic Arts' Origin.
As Steam expanded its userbase to more than 40 million accounts and its game selection to over 1,800 titles, the service doubled the amount of content it delivered year-over-year. It also set a new record during a recent holiday promotion that saw 5 million simultaneous users logged in.
Valve notes that it saw a 67 percent year-over-year increase in the number of registered games featuring its Steamworks API, with players registering over 14.5 million Steamworks-enabled copies of games like The Elder Scrolls V: Skyrim and Call of Duty: Modern Warfare 3.
Valve will continue to face increasing competition in 2012 from new digital platforms. Notable among them is games-by-mail service GameFly, which is set to expand its services into the digital realm a la Netflix.