The science wire Eurekanet says that the comet Tempel-1 has gone quiet ten days after the collision with the Tempel-1 probe. The absence of a prolonged "active site," or jet, may limit observations from the pristine materials from the inside of the comet. Eurekanet links over to the European Southern Observatory which confirms that the comet does not have a visible jet.
Tempel-1 has been around the sun many times, so its exterior has been chemically modified. One goal of the impact experiment was to excavate through this outer part, to let out the inner stuff which would be representative of the chemistry of the forming solar system (in the vicinity of Jupiter). Without a prolonged jet, the astronomers have got "only" the 40 hours of observation from immediately after the collision. Coincidentally, an active site had opened up spontaneously before Deep Impact arrived, so the observatories will have that information as well.
I can't find much more on this topic yet.
Wikipedia is already up with a very nice summary of the mission. The technical demands of this mission are unbelievable.