rose 23 percent from last year, while Thanksgiving sales rose 32 percent year over year, Mercent estimated.
What we don't know is whether this is a zero-sum game or whether there is some benefit to retailers by broadening the holiday shopping window, Best said. There is risk that real growth in retail for the entire holiday may be overestimated based on these early numbers.
Scot Wingo, chief executive of e-commerce company ChannelAdvisor, calls the early online shopping season Cyber 5, referring to Thanksgiving, Black Friday, Saturday, Sunday and Cyber Monday.
The online players are definitely participating more on Thanksgiving and Black Friday, so Cyber Monday is being shared with other holidays now, Wingo said.
ChannelAdvisor clients saw same-store sales on Amazon.com jump 35 percent on Thanksgiving and 38.3 percent on Black Friday, compared with a year earlier.
Client same-store sales on eBay's online marketplace rose 27 percent on Thanksgiving and 31 percent on Black Friday, compared with a year earlier. Last year's year-over-year growth was about 15 percent for eBay, according to ChannelAdvisor.
EBay usually grows more slowly early in the holiday season and then ramps up later as retailers run out of hot products and shoppers turn to eBay sellers for those items.
EBay's strong start this year is driven partly by the company's success in attracting mobile shoppers through shopping apps on smart phones and tablets, Wingo said.
EBay said on Saturday that the volume of mobile transactions on its online marketplace jumped 153 percent on Black Friday, compared with a year earlier. PayPal, the payments division of eBay, saw Black Friday volume almost triple, year over year.
Purchases from mobile devices accounted for 16.3 percent of online sales on Black Friday, up from 9.8 percent in 2011 and 3.2 percent in 2010, according to IBM data. Apple Inc's iPads and iPhones led the charge, with owners using the devices to browse and buy on retailer websites.
SHOPPERS 'WANT TO SPEND'
Overall, the percentage of sales from online shopping is expected to rise. But while retailers bring in more revenue from online shopping, they may also face some higher costs in terms of shipping a larger number of packages