Quakecon 2011 is in full swing, and while the annual Keynote address was chock full of RAGE-related news, Doom 4 was nowhere to be seen.

There is no plan or team in place for a future Quake title.
The id Tech 4 engine (Doom 3, Quake 4, Brink) will be come open source "later this year."
Quake Live is a "business failure" - it loses money for id Software - but they don't plan on shutting it down anytime soon.
Doom 4: Will probably run at 30 Hz for single player, and 60 Hz for MP. Most of the Rage dev team will migrate to Doom 4 once the game ships later this year.
Rage 2 is going to happen expected, assuming Rage 1 is a success.
Rage will not have dedicated servers, and there will be no Eyefinity support at launch.
id Software currently has no Mac or Linux strategy.
We'll be posting more news as the weekend progresses, and we should have some id Software interviews to post as well in the coming days. Stay tuned!