Comment by nottorp

Carmack has a post from ages ago wondering why no one does that with the ID engines they open sourced, which were pretty current back then. He was talking about the quake (2?) source code dumps i think.

Edit: ohh i found it:

http://www.gamespy.com/articles/641/641662p6.html

The GPL license will allow people to take the Quake 3 engine and even go so far as to release a commercial product with it - provided that the source code is published alongside. Nobody has done this with any of the Quake engine games yet, but he hopes to see it happen someday.