United States of America Rwinterhalter wrote a great article about Quake on 1UP. Enjoy it:
"Quake may be the most influential game of all time. Not the best game, not the most innovative, but the most influential. Without it, the industry would be a very different place today. It gave rise to many of aspects of modern gaming that we take for granted. Its developers, modders, and even the very code of the game itself are ubiquitous in the industry today. Id Software's 1996 FPS gave rise to 3D gaming, client/server online play, the most prolific mod scene in history, multiplayer clans, server browsers, eSports, mouse-look as the PC control standard, Valve and dozens of other companies, and even 1UP's sister website, GameSpy. Without Quake, it's unlikely another game that featured the same suite of innovations would have come along. We would have had to wait for each of those things one at a time."
Have fun reading the full article.

Link: Article on 1up.com