According to figures from internet analytics firm comScore, shoppers spent a record $1bn online on four separate days.
As consumers increasingly access the internet on-the-go through mobiles and tablets, the ability to shop anywhere and at anytime has helped 2012 become the largest ecommerce year to date.
The week of December 8th became the biggest spending week in history, generating over $6.9bn in online sales, comScore said.
"This past workweek saw four days surpass the billion dollar spending threshold during the heaviest five-day online shopping period on record," said comScore chairman Gian Fulgoni.
"With this most recent week in the books, the peak spending period may now be in our rear-view-mirror - but the online holiday shopping season is not over yet. We should have one more headline day on Free Shipping Day this Monday the 17th as the procrastinators among us scramble to order gifts in time for Christmas next week," he added.
The growth rate for 2012 compared to 2011 is expected to be well over 10%, Fulgoni said. "For the season-to-date, the growth rate based on corresponding days last year is 13%. But, with two extra shopping days between Thanksgiving and Christmas this year, we still expect that the full season will realize a growth rate well north of 13%," he said.
Cyber Monday this year became the heaviest online spending day in history, with a whopping $1.465bn spent in just one day.
A report by Experian revealed that UK consumers made 112 million visits to online retail sites that day, a 32% increase from the year before. Amazon had the largest increase in market share of visits this year representing 12% of all retail results, up from 10% last year.
Mobile devices were widely used for shopping on Cyber Monday with eBay UK mobile and Argos Mobile being the third and sixth fastest moving websites.
"There is still plenty of shopping time between now and Christmas however, and in particular we are expecting a lot of last-minute panic buying online on Christmas Eve as consumers take advantage of click-and-collect services," said James Murray, digital insight manager for Experian marketing services.
"Marketers need to be aware of these trends so they can engage with their customers at the night time to maximise sales in what could be a bumper Christmas year for online retail," he added.