Here's part of an interesting article from this week's Economist:

An important reason why the American economy has been so resilient and recessions so mild since 1982 is the energy of consumers. Their spending has been remarkably stable, not only because drops in employment and income have been less severe than of old, but also because they have been willing and able to borrow. The long rise in asset prices--first of stocks, then of houses--raised consumers' net worth and made saving seem less necessary. And borrowing became easier, thanks to financial innovation and lenders' relaxed underwriting, which was itself based on the supposedly reliable collateral of ever-more-valuable houses. On average, consumers from 1950 to 1985 saved 9% of their disposable income. That saving rate then steadily declined, to around zero earlier this year (see chart). At the same time, consumer and mortgage debts rose to 127% of disposable income, from 77% in 1990.

Those forces have now reversed. The stockmarket has fallen to the levels of a decade ago. House values have fallen 18% since their peak in 2006. Banks and other lenders have tightened lending standards on all types of consumer loans.

As a consequence, consumer spending fell at a 3.1% annual rate in the third quarter (in part because tax rebates boosted spending in the second), the steepest since the second quarter of 1980 when Jimmy Carter briefly imposed credit controls. More such declines are likely to follow. Richard Berner of Morgan Stanley projects that in the 12 months up to the second quarter of next year real consumer spending will fall by 1.6%--a post-war record. "The golden age of spending for the American consumer has ended and a new age of thrift likely has begun," he says.