Recently there has been a lot of talk about how the insurgency in Iraq is 'different' - this reminds me of the new economy talk in the late 1990's. The thing that is different with the insurgency is that communicaitons has increased the speed of innovation. In effect bad ideas go away faster (along with the people trying them out) and newer/better ideas are adopted, improved upon and shared with others. In previous insurgencies the lines of communicaitons were tenuous and usually involved people having to travel for training. With the ease of xerox and the internet, ideas are cycled through much more rapidly, leading to a deadlier force.
Col John Boyd coined the phrase "get inside the enemies OODA Loop" (OODA = Observation, Orientation, Decision, Action, see http://www.mindsim.com/MindSim/Corporate/OODA.html) meaning if you can make decisions faster than your enemy you will win. In effect it allows you to make more bad decisions and find interesting combinations of attack.