Doom 4 has been indefinitely postponed, according to a rumour on Kotaku. The site, which quotes a source which it states is "claiming to be close to the publishers of the recently-launched RAGE", suggests work on the sequel has been halted due to poor RAGE review scores and a lack of confidence in id Software management.
RAGE earned a solid 8/10 in our RAGE review. We said that "RAGE is a technical powerhouse, and if you can overlook the bits that don't quite work, you'll find one of the most exciting shooters we've had in years".
RAGE currently sits on a Metacritic of 81, which can't really be classed as bad. Considering the length of RAGE's development the game might not have delivered exactly what was expected, but to postpone Doom 4 seems like an overreaction if true.