Doom (or DOOM) is a 1993 computer game by id Software that is among the landmark titles in the first-person shooter genre. It is widely recognized for its pioneering use of immersive 3D graphics, networked multiplayer gaming on the PC platform, and the support for players to create custom expansions (WADs). Distributed as shareware, Doom was downloaded by an estimated 10 million people within two years, popularizing the mode of gameplay and spawning a gaming subculture; as a sign of its impact on the industry, games from the mid-1990s boom of first-person shooters are often known simply as "Doom clones". Its graphic and interactive violence has also made Doom the subject of much controversy reaching outside the gaming world. According to GameSpy, Doom was voted by industry insiders to be the #1 game of all time.