Over at Gamespy you can check out the final installment of the Masters of Doom excerpts, which covers Doom multiplayer and the final uploading of the shareware wad. There's also a nifty interview with a bunch of ex-id guys, namely John Romero, Tom Hall, Jay Wilbur, Sandy Peterson and Mike Wilson. Here's a small snip:
GameSpy: How would the industry be different if id had never happened?
John Romero: I can't really even guess [at] that answer because I feel that so much happened because of DOOM. I mean, it just changed *everything* ... the perception that the PC was a serious gaming system, multiplayer games were here to stay, 3D was the future of games, giving out demos was a great thing (back then there were no demos), and the fact that the content was so violent and shocking. It changed so much.
Also I noticed that the Gamespy Grudgematch is Doom vs Quake, so be sure to drop in a vote for Doom as well. Unless of course you like Quake better or something, you weirdo.