Word of Abu Musab al-Zarqawi's death spread rapidly among his followers. By early Thursday, Internet chat rooms frequented by Islamist extremists were buzzing. Among those reading along was a young American by the name of Evan Kohlmann, who has become a sought-after expert on the sites.
The 27-year-old has risen to become one of the most widely-quoted terrorism analysts in the world. He spends his days tracking extremist Web sites -- often penetrating ones that U.S. officials can't crack. Kohlmann monitors blogs that cover subjects ranging from which suicide vest works best to how to mix homemade ricin poison. His expertise has made him a sought-after witness in government trials, and in the press.