NEW YORK (CNNMoney.com) -- Americans spent more than $1 billion on Cyber Monday, making it the biggest online shopping day in history, digital marketplace research firm comScore said Wednesday.
Sales totaled $1.028 billion on Monday, a 16% increase versus a year ago, and a new one-day record.
Cyber Monday is the first Monday after Thanksgiving and is a relatively recent retail phenomenon, compared to Black Friday, the day after Thanksgiving. Many retailers traditionally open their doors at midnight on Black Friday, attracting shoppers with heavily advertised discounts.
"The online holiday shopping season has clearly gotten off to a very strong start, which is welcome news," said comScore Chairman Gian Fulgoni in a statement.
Fulgoni did attach one caveat, noting that heavier than normal promotional and discounting activity contributed to the bump in sales.
ComScore also reports that between Nov. 1 and Nov. 29 of this year online shoppers racked up $13.55 billion in sales, an increase of 13% over the previous year.
48.9% of Cyber Monday orders were placed from work computers, comScore said, a slight decline from last year.
Cyber Monday might be just the start of billion-dollar online sales days, which Fulgoni says he expects to see more of as the shopping season progresses.
On Tuesday, analytics group Coremetrics released a similar report that said Cyber Monday sales in the U.S. were up 19.4% in 2010 compared to last year.
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