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.
Doom (1993 video game)
With the release of "Doom", id Software, quickly found itself making $100,000 daily. Sandy Petersen later remarked that the game "sold a couple of hundred thousand copies during its first year or so", as piracy kept its initial sales from rising higher. Experts estimate that the game sold approximately 2-3 million physical copies from its release through 1999. According to PC Data, which tracked sales in the United States, the "Doom" shareware edition sold 1.15 million copies by September 1999. The "Ultimate Doom" SKU reached sales of 787,397 units by that date. At the time, PC Data ranked them as the country's eighth- and 20th-best-selling computer games since January 1993. In addition to its sales, the game's status as shareware dramatically increased its market penetration. "PC Zone"s David McCandless wrote that the game was played by "an estimated six million people across the globe", while other sources estimate that 10–20 million people played "Doom" within 24 months of its launch.