In addition to the thrilling nature of the single-player game, the deathmatch mode was an important factor in the game's popularity. "Doom" was not the first first-person shooter with a deathmatch mode; "Maze War", an FPS released in 1974, was running multiplayer deathmatch over ethernet on Xerox computers by 1977. The widespread distribution of PC systems and the violence in "Doom" made deathmatching particularly attractive. Two-player multiplayer was possible over a phone line by using a modem, or by linking two PCs with a null-modem cable. Because of its widespread distribution, "Doom" hence became the game that introduced deathmatching to a large audience and was also the first game to use the term "deathmatch".