Online retail sales skyrocketed this holiday season, as consumers increasingly took to shopping from the comfort of their homes. Online sales using Visa-branded cards for the week ended Dec. 26 were $1.8 billion, up 58% over the year-earlier period, while the number of online transactions reached 24 million, up 43% from a year ago, according to Visa USA's SpendTrak report.

The data indicates a shift toward more last-minute shopping online. In 2002 and '03, the peak period for online sales occurred two weeks after Thanksgiving, then dropped off sharply, according to market-research firm ComScore Networks. In 2004, Visa's peak online sales also took place two weeks after Thanksgiving, but there was no drop-off afterward; sales stayed at or near peak level until Christmas.

Also, Amazon.com Inc. reported last week that the period between Nov. 25 and Dec. 24 was the "busiest holiday season ever." The online retailer said it set a single-day record this season of more than 2.8 million units ordered, or 32 items per second. On its peak day, Amazon shipped more than 2 million units to 217 countries, the company said.

The trend toward last-minute online shopping reflects the use of better forecasting techniques by retailers, says David Schatsky, senior VP at market-research firm JupiterResearch. Retailers are becoming more sophisticated at tracking online sales to determine how much inventory to keep on hand, he says. That, in turn, lets them ship later in the season and offer consumers later cutoff dates for making online purchases.