The price of crude oil has dropped by 50 percent in the past year. Shell won't be exploring for oil in the Arctic Ocean after all. In the Gulf of Mexico, leases for new oil wells aren't selling. Tens of thousands of workers are being laid off, from Texas to North Dakota to Central Canada. Hydraulic fracking equipment is lying idle. Is it just another decline in a boom-and-bust industry or the beginning of the end of the oil economy? What's the immediate impact on the American consumer?