Although the season kicked off with a bang, there were fears that consumer confidence would fall as the end of the year approached. That did not happen, with people continuing to fill their virtual shopping carts until the very last minute; 10 individual days surpassed $1 billion in spending.

According to comScore, the final tally for online spending for the months of November and December was $37.2 billion, representing a 15 percent increase over last year.

ComScore tracks purchases made on Web sites from a fixed Internet connection, excluding spending done via mobile phones and tablets, so presumably the numbers could be higher.

While the numbers being reported sound positive, some analysts worry if they were enough to give giants like Amazon the growth rates needed to hit expectations. Wall Street analysts are expecting Amazon to post a fourth-quarter growth rate of 38 percent, which would mean it would have to be growing twice as fast as the average market.

But Chase Paymentech’s annual Cyber Holiday Pulse Index painted a rosier picture of the holiday season. Based on tracking 50 of the leading online merchants in the U.S., the report found that during the final two months of the year, transactions were up 37 percent and sales rose 25 percent.

One of the reasons for the huge gains, it said, was because Christmas fell on a Sunday this year, allowing merchants to guarantee shipping much later into the week and giving consumers more time to make online transactions.

To be sure, the increase in online shopping is coming from somewhere — most likely at the expense of traditional retail, which is expected to report a less impressive 4 percent growth rate this year.

“It’s clear that e-commerce continues to gain market share from traditional retail due to the attractiveness of the Internet’s convenience and lower prices,” said comScore Chairman Gian Fulgoni. “Consumers were especially attracted to the deals and discounts available through digital channels -– particularly free shipping, which occurred on well over half of transactions this season.”

The most impressive finding of the season was that 10 individual days surpassed $1 billion in spending, compared to only one day in 2010.

Here is a list of the 10 biggest online shopping days in 2011, led by Cyber Monday:

(Image credit: iStockphoto.com/mbortolino)

Black Friday. Cyber Monday. Mobile Tuesday.

What’s next, Debt Consolidation Loan Wednesday? 401(k) Withdrawal Thursday? Pavlov’s Dog Friday?

Try Green Monday. Turns out, the Monday two weeks before Christmas is also a shopping holiday, one apparently held in celebration of the seasonal deadline for free shipping. “This is the last minute [to ship]” said eBay (EBAY) executive Jim Griffith. “It’s do or die.”

Although, given the current economic climate, it’s “do less.” Because according to Chase Paymentech’s Cyber Holiday Pulse Index, the average dollar amount of purchases made on Cyber Monday this year was down 12 percent from last year (click on the charts below). Though there are 14 percent more total transactions this year over last, the typical shopper spent $7.19 less per transaction. “Cyber Monday was very interesting,” said Aaron Press, Director of Market Analysis for Chase Paymentech. “Transaction volume was well ahead of last year for that day, but sales growth was meager. For the entire holiday season, the slower rise in sales volume compared to the steeper increase in transactions has resulted in the average ticket being lower on most days.”

Black Friday. Cyber Monday. Mobile Tuesday.

What’s next, Debt Consolidation Loan Wednesday? 401(k) Withdrawal Thursday? Pavlov’s Dog Friday?

Try Green Monday. Turns out, the Monday two weeks before Christmas is also a shopping holiday, one apparently held in celebration of the seasonal deadline for free shipping. “This is the last minute [to ship]” said eBay (EBAY) executive Jim Griffith. “It’s do or die.”

Although, given the current economic climate, it’s “do less.” Because according to Chase Paymentech’s Cyber Holiday Pulse Index, the average dollar amount of purchases made on Cyber Monday this year was down 12 percent from last year (click on the charts below). Though there are 14 percent more total transactions this year over last, the typical shopper spent $7.19 less per transaction. “Cyber Monday was very interesting,” said Aaron Press, Director of Market Analysis for Chase Paymentech. “Transaction volume was well ahead of last year for that day, but sales growth was meager. For the entire holiday season, the slower rise in sales volume compared to the steeper increase in transactions has resulted in the average ticket being lower on most days.”