The clock is ticking. There's still time. But not much.

With Christmas just a day and a half away, retailers around the Web have been hanging banners on their sites reminding customers that their last-minute purchases can still arrive in time for the holiday.

At Amazon.com (NASDAQ: AMZN), the largest world's biggest e-commerce vendor, the home page displays an image of the Kindle e-reader, wrapped in a red ribbon alongside red and green text screaming "Kindle for Christmas" and offering free one-day shipping for the device -- which Amazon claims has been its best selling item this holiday season. At the top of the screen sits a clock, ticking down the seconds until the free in-time shipping offer expires, at midnight tonight.

For the rest of its wares, Amazon is advising customers to place their orders by 4:30 pm PT to receive them on Christmas Eve, using the firm's one-day shipping service.

Amazon's not the only one pushing eleventh-hour action. Toys "R" Us is talking up its express shipping option -- ending at 3 pm ET -- on its Web site, while over at NewEgg.com, the computer and electronics vendor, consumers have until 3 pm PT to get their orders in to ensure delivery by Christmas. Meanwhile, BestBuy.com is highlighting store pickup for online orders placed before 3 pm local time on Christmas Eve and showcasing last-minute deals on devices like the Nintendo Wii and Apple iPod Touch.

Online Selling Gets Extended

The waning hours of the holiday shopping crush put a cap on a season that industry analysts have described as something of a departure from previous years. From Monday Dec. 14 through Sunday Dec. 20, the last full week before the holiday, online sales were up 14.6 percent from the comparable period last year, according to Web marketing firm Coremetrics.

For Friday and Saturday of that week, sales were up 24 percent from last year, and up 20 percent on Sunday.

"In past years, we have seen a big drop in online sales the weekend before Christmas largely because of the end of free shipping," John Squire, Coremetrics' chief strategy officer, said of the better-than-expected run-up to the holiday. "But this season broke with tradition. We saw a lot of online buying starting late Friday afternoon and continuing over the weekend. Clearly, retailers have done a tremendous job of pushing bargains not just on a specific day, but throughout the season."

Online metrics firm comScore reported a similar uptick late in the season, tallying double-digit increases in spending over the weekend, compared to a modest 4 percent improvement in overall sales since Nov. 1.

Of course, the weather did its part to nudge e-commerce vendors into the black. Over the weekend, the East Coast was socked with a record-setting snowstorm that kept shoppers at home, redirecting money that could have been spent at the malls into online coffers.

"The major snowstorms hitting the eastern seaboard over the weekend appear to have given holiday e-commerce an additional boost, resulting in the heaviest online spending week on record at $4.8 billion," comScore Chairman Gian Fulgoni said in a statement.

"Consumers have clearly continued to spend online later into the season this year," Fulgoni added. "Retailers have been very aggressive with late season promotions while informing consumers that they could still get their purchases shipped in time for Christmas, and these tactics seem to be paying off."

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