...Preparedness activity is difficult to track statistically, since people who take measures are usually highly circumspect by nature, said Jim Rawles, the editor of www.survivalblog.com, a preparedness Web site. Nevertheless, interest in the survivalist movement “is experiencing its largest growth since the late 1970s,” Mr. Rawles said in an e-mail, adding that traffic at his blog has more than doubled in the past 11 months, with more than 67,000 unique visitors per week. And its base is growing. “Our core readership is still solidly conservative,” he said. “But in recent months I’ve noticed an increasing number of stridently green and...