ComScore (www.comscore.com), a company that “measures the digital world,” y reported holiday season U.S. retail e-commerce spending for the first 26 days of the November-December 2012 holiday season.

For the holiday season-to-date, US$16.4 billion has been spent online, marking a 16% increase versus the corresponding days last year. Cyber Monday reached $1.465 billion in online spending, up 17% versus the same period a year ago, representing the heaviest online spending day in history and the second day this season (in addition to Black Friday) to surpass $1 billion in sales.

“Despite some news reports suggesting that Cyber Monday might be declining in importance, the day has once again set an online spending record at nearly $1.5 billion,” says ComScore Chairman Gian Fulgoni. “However, it is also clear that the holiday promotional period has begun even earlier this year, with strong online sales occurring on Thanksgiving Day and Black Friday. Now, we shall see the extent to which continuing and attractive retailer promotions are able to boost sales for the remainder of the week.”

Cyber Monday saw digital content and subscriptions continue to set the pace among product categories with a year-over-year growth rate of 28%. Consumer electronics, buoyed by gains in smartphone sales, ranked second at 24% while tablet sales helped the computer hardware category post a 22% growth rate. Video games, consoles and accessories (up 18%) and jewelry and watches (up 17%) rounded out the top five.

Nearly half of dollars spent online at U.S. websites originated from work computers (47.1%), down slightly from last year. Buying from home comprised the majority of the remaining share (47.2%) while buying at U.S. websites from international locations accounted for 5.7% of sales.