Doom (1993 video game)
Because id planned to self-publish the game, as the game neared completion they had to set up the systems to sell the game. Jay Wilbur, who had been brought on as CEO and sole member of the business team, planned the marketing and distribution of "Doom". He felt that the mainstream press was uninterested in the game, and as id would make the most money off of copies they sold directly to customers—up to 85 percent of the planned US$40 price—he decided to leverage the shareware market as much as possible, buying only a single ad in any gaming magazine. Instead, he reached out directly to software retailers, offering them copies of the first "Doom" episode for free, allowing them to charge any price for it, in order to spur customer interest in buying the full game directly from id.
Doom WAD
Immediately after the initial shareware release of "Doom" on December 10, 1993, enthusiasts began working on various tools to modify the game. On January 26, 1994, Brendon Wyber released the first public domain version of the Doom Editing Utility (DEU) program on the Internet, a program created by "Doom" fans which made it possible to create entirely new levels. DEU continued development until May 21 of the same year. It was made possible by Matt Fell's release of the Unofficial "Doom" specifications. Shortly thereafter, "Doom" enthusiasts became involved with further enhancing DEU. Raphaël Quinet spearheaded the program development efforts and overall project release, while Steve Bareman lead the documentation effort and creation of the DEU Tutorial. More than 30 other people also helped with the effort and their names appear in the README.1ST file included with the program distribution. Yadex, a fork of DEU 5.21 for Unix systems running X, was later released under the GNU/GPL license. (Carmack additionally released the source code for the utilities used to create the game, but these were programmed in Objective-C, for NeXT workstations, and were therefore not directly usable for most people, who were PC users.)