Glenn Greenwald has a terrific insight into the world of contemporary American right-wingers.
In fairness, I should say that I've seen examples of the same phenomenom in the liberal blogosphere. Not long ago I saw some liberal bloggers who claimed that Michelle Malkin had posted the phone numbers of members of UC Santa Cruz "Students Against War" (SAW). The original posts failed to mention that those phone numbers had first been included in a press release that SAW itself had put out. Yet the outrage trickled down the liberal blogosphere as blogger after blogger referred back to the original claims of this heinous crime committed by Malkin.
However, I see this type of thing much more often in the right-wing-nut-job half of the blogosphere. And what's more important is that I almost never see the right-wingers apologizing or correcting themselves after the facts are unmistakably on the table. The notable exceptions here (among the bloggers I read) are Andrew Sullivan and Greg Djereijan. Which, I suspect, is why true RVNJ's no longer think of them as "real" conservatives.
UPDATE: Glenn's powerful follow-up and response to his critics. His writings are amazing. I just pre-ordered his #1 Amazon ranked book. Wifey yelled at me (citing a history of buying books I don't read) but I don't care - I'm a fan! To me this guy is like the Yankees, Braves, Hawks and the Norwegian national soccer team rolled into one! :)