It's the day of the online deal.

Millions of shoppers are expected to click on items on Monday as retailers rev up deals to grab online holiday shopping dollars on the first working day after the busy holiday weekend.

But this year so-called Cyber Monday seems to have stretched into Cyber Week or even Cyber Month, with retailers from Amazon to Wal-Mart rolling out online deals since the beginning of November.

Still, Cyber Monday is expected to be the busiest online shopping day of the year. Research firm comScore expects Cyber Monday expects sales of $2 billion, up from about $1.47 billion last year. Online sales account for about 10 percent of total holiday spending.

In terms of total Thanksgiving weekend sales, a record 141 million people were expected to shop in stores and online over the four-day period that ended Sunday, up from last year's 137 million, according to the results of a survey of nearly 4,500 shoppers conducted for The National Retail Federation.

But total spending is expected to fall for the first time ever since the trade group began tracking it in 2006, according to the survey that was released on Sunday. Over the four days, spending fell an estimated 2.9 percent to $57.4 billion.

Shoppers, on average, were expected to spend $407.02 during the four days, down 3.9 percent from last year. That would be the first decline since the 2009 holiday shopping season when the economy was just coming out of the recession.

The survey underscores the challenges stores have faced since the recession began in late 2007. Retailers had to offer deep discounts to get people to shop during the downturn, but Americans still expect those "70 percent off" signs now during the uneven economic recovery.

Stores may have only exacerbated that expectation this year. By offering bargains earlier in the season, it seems they've created a vicious cycle in which they'll need to constantly offer bigger sales to get people to spend. That's because shoppers who took advantage of "holiday" deals before Thanksgiving may have deal fatigue and are cautious about buying anything else unless it's heavily discounted.

"The economy spoke loud and clear over the past few days," said Brian Sozzi, CEO and chief equities strategist at Belus Capital Advisors. "We are going to see an increase in markdowns."

Matthew Shay, president and CEO of The National Retail Federation, said that the survey results only represent one extended weekend in what is typically the biggest shopping period of the year. The combined months of November and December can account for up to 40 percent of retailers' revenue.

Overall, Shay said the trade group still expects sales for the combined two months to increase 3.9 percent to $602.1 billion. That's higher than the 3.5 percent pace in the previous year.

But the early start appeared to pull sales forward. Black Friday sales fell 13.2 percent from the previous year to $9.74 billion, according to Chicago-based technology firm ShopperTrak. But combined spending over Thanksgiving and Black Friday rose 2.3 percent to $12.3 billion compared with a year ago.