After an al Qaeda suicide bomber killed seven CIA employees, and a Jordanian intel agent last December 30th, several CIA officials mentioned vengeance. The CIA has been known to go after those who kill CIA operatives. So it was noted that in the three weeks after the December 30 bombing, there have been eleven CIA UAV missile attacks in Pakistan, killing at least 90 Taliban and al Qaeda members. In the 17 months that the CIA UAV campaign has been underway in earnest (with few restrictions by Pakistan, which provides bases for the UAVs to operate from), there have usually been 3-4 attacks a month, not one every other day.
This sharp increase in UAV attacks was probably not ordered up as a vengeance campaign, but was a coincidence. The CIA and U.S. Army Special Forces have been building, and working, an informant network, on both sides of the border, for years. It's known that the CIA has a target list of over 400 Taliban, al Qaeda and drug gang leaders. The CIA handles most of the data collection, and actual hits on the targets. Finding these targets is a much larger operation than the effort to keep twenty or so armed UAVs in the air.
The CIA is also upgrading its UAV fleet from one ton Predators, to 4.6 ton Reapers. The agency currently has six Reapers, and in the next year, will get eight more. The Reaper can carry more Hellfire missiles, fly higher (thus covering a larger area) and stay up longer. The use of the Reaper has led to more multi-missile attacks, which makes it possible to take down large structures, or multiple vehicles in a convoy. The Reaper can also carry a 500 pound JDAM, for really big jobs. But the 106 pound Hellfire is preferred, as it keeps the civilian casualties down.
The CIA UAV campaign, especially its recent success (the December 30 bombing was in retaliation for an earlier attack that killed the head of the Pakistani Taliban), has caused Pakistani terrorists to change how they operate. Many Taliban will not take a private vehicle on the road, but instead will travel by bus, surrounded by civilians. But the terrorists are still vulnerable when they rest for the night, and many will sleep outside, away from structures. This doesn't work so well in the Winter, but paranoia is increasing, and that's a welcome side effect, and a form of vengeance.