Moving aside from the middle-eastern debate...
As a veteran of Usenet, I find myself amused that the sort of "quote and response" style that was ubiquitous there somehow corresponds to a complete annihilation of posts and articles when applied to Weblogs. "Fisking", while an interesting term, doesn't translate as much to rhetorical and argumentative superiority as some people think it does. As any cursory examination of any webboard or Usenet archive will show, it usually just leads to "back-and-forth" quotation, or what I suppose would be "mutual fisking".
More than that, it's actually a somewhat problematic form of argument. Why? Well, in many respects any essay-format argument depends on its structure and themes in order to be understandable, and breaking that structure up into smaller chunks and attacking each chunk leads to a "missing the forest for the trees" style of argument that attacks supporting arguments but misses the main point.
More than that, it can actually be incredibly intellectually dishonest, because "back-and-forth fisking" usually means that points that aren't as vulnerable are discarded instead of answers, and unless the person who wrote the original post is very careful, they might be stuck defending bad points because the good ones were conveniently ignored... or it may be that only one small sub-point was attacked, and viewers may get the impression that that small point taken out of context was intrinsic to the article and/or the views held by the person, instead of an unimportant mistake.
Anyway, you don't need to take my word for it. Go over to Google some time and read some of the nastier arguments in your typical politics group (or video gaming group... political warriors have nothing on the viciousness of adherents to different console platforms). Am I guilty of this sort of thing? Yes, everybody is, and I don't necessarily believe that "fisking" is intrinsicially invalid. Like any technique, however, people who use it and people who encounter it need to approach it critically.