I enjoyed the Joseph Stiglitz lecture at Lindau. He presented two main areas as a research agenda in macroeconomics: networks and contagion; and structural transformations in the economy.
I'm very interested in possible structural transformations, but it seems Stiglitz has in mind productivity improvements in one sector exceeding growth in demand and causing an economy wide slump as labour gets trapped in the declining sector. The example is agricultural productivity improvements prior to the great depression only sorting itself once this surplus labour had managed to move to manufacturing.
The hypothesis is perhaps this is happening now and we are seeing manufacturing productivity gains outstripping demand, and causing a slump that will be righted only once enough formerly manufacturing labour has made its way to services.
This doesn't seem right to me and I'm concentrating on the structural transformation implied by a reduction in the energy flux to the economy. Stiglitz's idea and model will be worth keeping in mind and/or following up though.