Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
While this week marks one year since the Doom 3 (id Tech 4) game engine was open-sourced under the GPL, there still isn't too much adoption by open-source game developers. The few forks of the id Tech 4 code-base also aren't seeing frequent activity.
The ioDoom3 project was announced by the ioquake3 developers immediately following id Software's announcement of the Doom 3 source-code drop. While backed by developers of ioquake3 and on Icculus.org where the the ioq3 engine continues to be wildly-used and deployed in various open-source titles, the ioDoom3 project hasn't taken off nearly as much.