MADRID (MarketWatch) — On the heels of data showing a record number of shoppers hit the stores over the holiday weekend, one digital-analysis group says spending on the most important shopping day of the year for online retailers, known as Cyber Monday, could reach $1.5 billion. 
 
 According to data released Sunday from comScore Inc. SCOR, -2.94% Cyber Monday spending is expected to exceed the $1.25 billion reached in 2011 for a gain of 20%. Spending on Cyber Monday — a marketing term coined back in 2005 — has more than doubled in the past five years. 
 
 “With Thanksgiving now behind us and most consumers returning to work tomorrow [Monday], we can look forward with anticipation to Cyber Monday, which according to norms we’ve observed over the past three years should be the heaviest online shopping day of the season with sales approaching $1.5 billion or even higher,” said Gian Fulgoni, comScore chairman, in a statement. 
 
 Black Friday stokes season hopes (28:44) Simon Constable and Andria Cheng discuss the holiday-shopping season, and Dan Neil reviews the 2013 Mercedes-Benz GL350. (Photo: AP) 
 
 Forecasts for Cyber Monday sales are slightly less buoyant than what comScore has reported for other key shopping days. The group’s data showed that online sales for Black Friday surpassed $1 billion for the first time. Sales rose 26% to $1.04 billion from $816 million seen on Black Friday in 2011. 
 
 ComScore data showed that Thanksgiving Day online sales grew 32% from a year earlier, to $633 million. 
 
 Fulgoni says the data point to the idea that Black Friday is growing more prominent in the e-commerce channel, particularly for shoppers who want to avoid heavy crowds. 
 
 “With Black Friday online sales up 26% and surpassing $1 billion for the first time, coupled with early reports indicating that Black Friday sales in retail stores were down 1.8%, we can now confidently call it a multichannel-marketing phenomenon,” added Fulgoni. Read comScore blog on historical importance of holiday spending to e-commerce. 
 
 Excluding auction sites such as eBay Inc. EBAY, -0.40% according to comScore, the top e-retailer for Black Friday sales was Amazon.com Inc. AMZN, +0.99% followed by the websites for Wal-Mart Stores Inc. WMT, -0.21% Best Buy Co. BBY, +1.01% Target Corp. TGT, +0.07% and Apple Inc. AAPL, +0.96% 
 
 Demand for digital books, audio and video content led those sales with a 29% gain over the prior year, followed by a 27% rise for toy sales and 23% for consumer packaged goods. 
 
 Reuters 
 
 Amazon.com was among those advertising Cyber Monday deals, such as much as $100 off on selected Sony laptops and a deal offering the Kindle Fire for $129, reduced from $159. Read about Amazon's Cyber Monday deals. 
 
 The National Retail Federation said Sunday that a record 247 million Americans shopped in stores and online during the four-day holiday weekend, a gain of 9% from the year-ago period. Within that number, 35 million Americans shopped online and in brick-and-mortar stores on Thanksgiving Day, and 89 million shopped on Black Friday. Read: Record count of holiday-weekend shoppers. 
 
 The NRF expects nearly 123 million consumers to shop on Cyber Monday. 
 
 Retailers kicked off shopping even earlier this year, with Wal-Mart, Toys “R” Us Inc. and Target among those offering “door-buster” promotions even earlier on Thanksgiving eve. Early traffic indicators were giving retailers some hope for what is a critical shopping period for them. Read: Black Friday gives retailers holiday hope. 
 
 Also read: Black Friday mania in consumer tech. ||||| FILE - In this Monday, Dec., 1, 2008, file photo, an Amazon.com employee grabs boxes off the conveyor belt to load in a truck at their Fernley, Nev., warehouse. Cyber Monday, coined in 2005 by a shopping... (Associated Press) 
 
 FILE - In this Friday, Nov. 29, 2008, file photo, carts full of merchandise ordered online are rolled to the main packing area for shipping at the Overstock.com warehouse, in Salt Lake City. Cyber Monday,... (Associated Press) 
 
 Cyber Monday, coined in 2005 by a shopping trade group that noticed online sales spiked on the Monday following Thanksgiving, is the next in a series of days that stores are counting on to jumpstart the holiday shopping season. 
 
 It's estimated that this year's Cyber Monday will be the biggest online shopping day of the year for the third year in a row: According to research firm comScore, Americans are expected to spend $1.5 billion, up 20 percent from last year on Cyber Monday, as retailers have ramped up their deals to get shoppers to click on their websites. 
 
 Amazon.com, which is starting its Cyber Monday deals at midnight on Monday, is offering as much as 60 percent off a Panasonic VIERA 55-inch TV that's usually priced higher than $1,000. Sears is offering $430 off a Maytag washer and dryer, each on sale for $399. And Kmart is offering 75 percent off all of its diamond earrings and $60 off a 12-in-1 multigame table on sale for $89.99. 
 
 Retailers are hoping the deals will appeal to shoppers like Matt Sexton, 39, who for the first time plans to complete all of his holiday shopping online this year on his iPad tablet computer. Sexton, who plans to spend up to $4,000 this season, already shopped online on the day after Thanksgiving known as Black Friday and found a laptop from Best Buy for $399, a $200 savings, among other deals. 
 
 "The descriptions and reviews are so much better online so you can compare and price shop and for the most part get free shipping," said Sexton, who lives in Queens, N.Y., and is a manager at a utility company. 
 
 Sexton also said that it's easier to return an online purchase to a physical store than it had been in previous years. "That helps with gifts," he said. 
 
 How well retailers fare on Cyber Monday will offer insight into Americans' evolving shopping habits during the holiday shopping season, a time when stores can make up to 40 percent of their annual revenue. With the growth in high speed Internet access and the wide use of smartphones and tablets, people are relying less on their work computers to shop than they did when Shop.org, the digital division of trade group The National Retail Federation, introduced the term "Cyber Monday." 
 
 "People years ago didn't have ... connectivity to shop online at their homes. So when they went back to work after Thanksgiving they'd shop on the Monday after," said Vicki Cantrell, executive director of Shop.org. "Now they don't need the work computer to be able to do that." 
 
 As a result, the period between Thanksgiving and Cyber Monday has become busy for online shopping as well. Indeed, online sales on Thanksgiving Day, traditionally not a popular day for online shopping, rose 32 percent over last year to $633 million, according to comScore. And online sales on Black Friday were up 26 percent from the same day last year, to $1.042 billion. It was the first time online sales on Black Friday surpassed $1 billion. 
 
 For the holiday season-to-date, comScore found that $13.7 billion has been spent online, marking a 16 percent increase over last year. The research firm predicts that online sales will surpass 10 percent of total retail spending this holiday season. The National Retail Federation estimates that overall retail sales in November and December will be up 4.1 percent this year to $586.1 billion 
 
 But as other days become popular for online shopping, Cyber Monday may lose some of its cache. To be sure, Cyber Monday hasn't always been the biggest online shopping day. In fact, up until three years ago, that title was historically earned by the last day shoppers could order items with standard shipping rates and get them delivered before Christmas. That day changes every year, but usually falls in late December. 
 
 Even though Cyber Monday is expected to be the biggest shopping day this year, industry watchers say it could just be a matter of time before other days take that ranking. 
 
 "Of all the benchmark spending days, Thanksgiving is growing at the fastest rate, up 128 percent over the last five years," said Andrew Lipsman, a spokesman with comScore.
– Black Friday sales were down year-on-year, but this year's Cyber Monday is expected to be the biggest online shopping day in history. Spending on the year's most important day for online sales is expected to top last year's $1.25 billion by around 20% to hit $1.5 billion, the chairman of digital analysis group ComScore tells MarketWatch. Online spending on the Monday after Thanksgiving has more than doubled over the last five years. But Black Friday itself saw plenty of online shopping, with sales nudging over $1 billion for the first time even as shoppers thronged brick-and-mortar stores, the AP reports. Analysts say that Cyber Monday may soon cease to be the busiest day for online sales, since fewer people now rely on computers at work to do their shopping. Online sales on Thanksgiving Day this year surged by 32% over 2011 to reach $633 million.