Americans are reining in their purchases at brick-and-mortar stores, but online? For many, it's still shop till you drop (or until your internet connection crashes).

Amazon.com recorded a 42 percent gain in sales in its fourth quarter, by far its biggest quarter because it includes the holiday shopping season. Online commerce overall did well this during the season, with sales rising 19 percent from a year, Bloomberg News reports. American retailers overall had only single digit gains.

More important, Amazon was upbeat about the year to come, suggesting that consumers may be more confident than recent economic data, including the G.D.P. report, might suggest. The company expects revenue of $18.8 billion to $19.8 billion for the year, above analysts' forecasts.

For the quarter, Amazon said net income more than doubled, to $207 million or 48 cents per share, compared with net income of $98 million, or 23 cents per share, in the quarter a year earlier. Sales rose 42 percent, to $5.7 billion. The profit matched Wall Street's estimates, but the revenue number topped them.

"This quarter showed accelerated sales growth and record operating profits," said Jeff Bezos, founder and chief executive of Amazon.com. "In our view, these unusual financial results are driven by one thing: continuously improving the customer experience."