That is the day retailers offer discounts and Web-only specials to people who make purchases online.
"Cyber Monday is still relevant. We're expecting about 129 million consumers to shop from their offices tomorrow, versus about 122 [million] last year," Mike Gatti with the National Retail Federation told CBS News.
But Gatti said this year, shoppers began partaking in online sales even before Thanksgiving.
"This is a huge evolution that we're seeing in the way customers shop and it's being brought on by mobile devices and all this new technology that we've got," he said.
Black Friday, which marks the start of the holiday shopping season, is so named because it is traditionally when retailers go from deficit into profits for the year.
"There will be a lot of products that go sale on Cyber Monday but if you miss it, don't despair. We're going to see deals throughout the holiday season, for that matter, after the holiday season. Both online and physical merchants are anxious to sell as much as they can and you better believe they're going to be doing everything possible to tempt consumers," CBS News technology analyst Larry Magid said.
"You don't have to go anywhere – that's for sure," online shopper Joe Rybandt told CBS 2's Amy Dardashtian. "You can do it in your pajamas from home."
But experts note that Cyber Monday can get competitive. To shop smart, consumers need to make a list, set up online accounts in advance, and use Web sites such as Google Products to compare prices.
"It will automatically pop up and see if there is any other better price on that product that you can find across the Web," said CNET Senior Editor Donald Bell.
If you have an Amazon Prime account, you can share it with up to four people and give the gift of free shipping.
"By adding your family members, or being added as a family member, you can add that free two day shipping and not have to spend a dime on a prime account," Bell said.
Select retailers are also offering deals of the hour. The time slots are posted on Shop.org.
Arlene Grudkowski loves shopping online – no lines, no waits and easy returns.
"You buy them if they have an outlet or a store near you, they don't fit, you bring them to the regular stores, so that makes it real easy," she said.
But even those who do not mind the crowds and are fresh off a weekend of shopping at the big retailers will hop online Monday, and many of them will do their shopping from work.
"Just discounts on toys," said Joey Schaljo of Manhattan. "I have nieces and nephews, so I buy a lot for them, and in all honesty I also buy for myself."
Others will access deals on the go using smart phones and iPads, making it easy to get addicted. But some say this time of year, a little shopping addiction is OK.
"I think most of us enjoy getting a bargain," said Denise Galiber of Harlem. "Whether it's real or perceived is not the point. It's really just the excitement of the season."
And how well retailers do on Cyber Monday will offer insight into Americans' evolving shopping habits.
With the growth in high-speed Internet access and the wide and increasing use of smartphones and tablet computers, 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, coined the term "Cyber Monday'' in 2005.
As a result, the period between Thanksgiving and Cyber Monday has become busy for online shopping as well.
Indeed, IBM Benchmark, which tracks online sales, said on Thanksgiving, a day that historically had not been big for online shopping, online sales this year rose 17.4 percent over 2011. Of that, mobile shopping, or shopping on smartphones and tablets, rose 18.3 percent. Meanwhile, online sales on Black Friday were up 20.7 percent.
For the overall holiday season, research firm comScore predicts online sales will be up 17 percent to $43.4 billion. And the firm expects online sales to 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.
"People years ago didn't have the kind of 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.''
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 held on the last day shoppers can order items with standard shipping rates and get them delivered before Christmas. That day usually falls in late December.
To maintain Cyber Monday's relevance some retailers are coming up with creative ways to improve service. Shop.org lets customers know which retailers are offering the best deals.
"You buy them, if they have an outlet or a store near you, and they don't fit you bring them to the regular stores so that makes it real easy," Arlene Grudkowski explained to CBS 2's Amy Dardashtian.
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.
Will you take part in Cyber Monday? Do you know what you will be buying, or are you waiting to see the deals? Sound off in the comments section below...
(TM and Copyright 2012 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)
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