Bill Keller, the top NYT editor, goes exploring:
Humans live along a continuum from doubt to faith. Wander far enough in the direction of faith and you reach the land of Nostradamus and of the Rapture (recently postponed). Wander too far in the other direction, past cynicism, through misanthropy, and you get to more or less the same zone of credulity: Osama bin Laden isn't dead, President Obama isn't American, global warming is a hoax.
Later in the column, Keller talks to scholar who makes an observation that seems applicable to conspiracy theorists on both the left and right:
Suspicion hardens into full-blown conviction when people lose faith in authorities, says [Peter] Knight, who edited "Conspiracy Nation: The Politics of Paranoia in Postwar America." The present day, he told me, when Internet access has sparked a proliferation of competing, self-appointed authorities, is a particularly fertile time for conspiracy theorists, who might ask: " "˜Why would you believe The New York Times? Why do they have a monopoly on truth? Surely Twitter and WikiLeaks are just as trustworthy.' " Knight added, "As soon as you lose faith that the mainstream media are telling the truth, anything is believable."
That is quite evident, as anyone who browses through the comments on most any climate blog can see.