"Social Epidemic" of Ideas

For those, like me, mystified by the variety of economic prognostications, this article by Robert Shiller, "An Echo Chamber of Boom and Bust," (http://www.nytimes.com/2009/08/30/business/economy/30view.html?_r=1&scp=1&sq=echo%20chamber&st=cse) provides some kind of explanation for recent reports of "green shoots" in the economy. Shiller is the author of Irrational Exuberance, a book which takes its title from testimony before Congress by Alan Greenspan. Sometimes Shiller is described as a "bear" but this article suggests that his views about the future of the economy are less a matter of mental stance and more a matter of what the data actually indicate.