Newsweek has an interesting story on that gives anecdotal evidence on the gap between the occupied and occupiers. From the outset, the US built self-contained bases (unlike the British) and limited contact with the population (as is the case with delayed US Embassy in Baghdad). The result was links to the population were denied, except in very few cases.
This is not just a different kind of war, it's also a different kind of American military than existed 40 or 50 years ago—one that may talk about engaging hearts and minds, but spends many of its resources trying to keep them at a distance. The insistent demands of "force protection" and the insidious efficiency of the insurgents' bombs and booby traps have isolated the American soldier from the population he or she was once tasked to liberate. We may not lament the lack of bars, dance halls and whorehouses for today's troops. But in Iraq there's hardly any human contact at all that isn't at the point of a gun.