Doom (1993 video game)
The ability for others to create custom levels and otherwise modify the game using WAD files turned out to be a popular aspect of "Doom". Gaining the first large mod-making community, "Doom" affected the culture surrounding first-person shooters, and also the industry. Several future professional game designers started their careers making "Doom" WADs as a hobby, among them Tim Willits, who later became the lead designer at id Software.
Official versions of Doom
In 2010, the game was pulled from the Xbox Live Marketplace because Activision, the game's publisher, no longer has the rights to maintain the game on the Marketplace, but as of January 20, 2012, it has been republished by Bethesda Softworks, the same company that published the Xbox Live Arcade version of "".