It is not only retail stores that are feeling the pinch as shoppers close their wallets just ahead of the holiday season. E-commerce sales, though still growing faster than retail, are hurting, too.

E-commerce spending growth slowed to 6 percent in the third quarter over the year before, down from 13 percent in the second quarter, according to comScore. Growth rates have declined every month since April, and September’s rate of 5 percent was the lowest recorded by comScore since it started tracking e-commerce in 2001.

Jeremy Liew, a venture capitalist and blogger, said he had not expected e-commerce to be hit so hard by this downturn because many e-commerce sites benefited from the last downturn. The shoe e-tailer Zappos.com, for example, grew during that period in part because e-commerce sites could buy online advertising more cheaply as ad sales slumped.

Mr. Liew — a managing director at Lightspeed Venture Partners who invests in e-commerce companies — has now revised his expectations after realizing that this downturn is hitting e-commerce much harder because consumer confidence is plummeting along with the stock market.

In October, the Conference Board’s Consumer Confidence Index fell to 38, an all-time low. By comparison, in the spring of 2000, as the Nasdaq composite index plummeted from its March 2000 high, the consumer confidence hovered around 140.

ComScore surveyed 1,000 consumers in October, and the results were similar. Eighty-two percent said they are more afraid about the economic future than ever before, and only 26 percent thought the economy would be better a year from now.

“Consumers have spent their way out of the last downturns,” Mr. Liew said, but not this time. Even those who have not lost their jobs and whose fundamental financial picture hasn’t changed are so shaken by events that they want to hold their money tight. “They ask, ‘Do I really need that digital camera? I can live without it,'” he said.

Indeed, once you have one pair of shoes, the rest are discretionary, a fact that forced Zappos.com to lay off workers last week. For Zappos.com and similar companies, falling sales are not about bad management, Mr. Liew said. “You can be excellent at executing, but if less people are showing up to buy, you’re not going to sell as much,” he said. (Lightspeed is not an investor in Zappos.com.)

The big exception is video games. Online sales of games and consoles grew most in the third quarter, up 60 percent from last year, said comScore. Sales of consumer electronics, computers and cellphones were flat, and sales of clothes, toys, jewelry, music and movies were down from a year ago.