This holiday e-commerce spending season is off to a flying start after Cyber Monday posted the largest-ever single day of online sales in the U.S. According to Adobe, consumers purchased $6.59 billion online during Cyber Monday, with purchases made on smartphones also breaking a record with $2 billion in sales.

The figures come from Adobe, which has been tracking shopping online in the last few days as retailers officially kick-off of holiday shopping season, the most important time of the year for their businesses. These early days are seen by many as a bellwether for how the next six weeks will play out.

Interestingly, Cyber Monday was the only day in the last five — the ‘start’ of the holiday shopping period that kicks off with the Thanksgiving long weekend, including Black Friday — that sales totals did exceed Adobe’s estimates. In fact, they fell just slightly short of the $6.6 billion it predicted.

Adobe — which extrapolates its figures by analysing 80 percent of online transactions to the 100 largest web retailers in the country — says that November has so far racked up $50 billion in online revenue, up 16.8 percent increase year-on-year.

2017, it projects, will be the first year to break $100 billion in online sales, which is actually a downward revision from Adobe’s previous figure of $107.4 billion. (As a point of comparison, online sales in the US reached $94.4 billion for the holiday season in 2016.)

Cyber Monday has traditionally been an especially strong day for buying online. The reason: it’s a perfect storm of discounts that kicked off on Friday, combined with people heading back to work after the long weekend, and therefore no longer able to go to physical stores as easily throughout the day to pick up deals. (We run through some of the more interesting bargains for tech products here.)

But interestingly, it seems that perhaps the most enthusiastic buyers came earlier in the weekend, leading to a Cyber Monday that broke records but still was perhaps not as powerful as initially expected.

Overall, Adobe said traffic was up 11.9 percent for the day (season average: 5.7 percent). As with other days in the long weekend, mobile has been very much a part of the story: 47.4 percent of visits (39.9 percent smartphones, the rest tablets), and 33.1 percent of revenues.

Notable in the mobile story is that of smartphone-based browsing and purchases. The record-high of $2 billion in sales made via smartphones was a whopping over 40 percent year-on-year increase: an outsized number compared to the rest of the increases across the board that ran between 10 and 20 percent.

As we’ve seen previously iOS — and specifically the iPhone — continues to lead ahead of Android when it comes to monetizing. Average order values on iOS devices was $123. On Android devices it was $110. Conversions, as you would expect, are also very strong on smartphones this year: mobile transactions are closing at a 12 percent higher rate versus a year ago. It seems that one takeaway might be that if you are making the effort to do your browsing on a smartphone, you must really want an item and you are being less casual about it.

“Shopping and buying on smartphones is becoming the new norm and can be attributed to continued optimizations in the retail experience on mobile devices and platforms,” said Mickey Mericle, vice president, Marketing and Customer Insights at Adobe, in a statement. “Consumers are also becoming more savvy and efficient online shoppers. People increasingly know where to find the best deals and what they want to purchase, which results in less price matching behavior typically done on desktops. Millennials were likely another reason for the dramatic growth in mobile, with 75 percent expecting to shop via their smartphone.”

The season has been record-breaking, both in terms of total sales and how shoppers are making a big shift to mobile to browse and buy.

Thanksgiving generated $2.87 billion in sales, Black Friday $5.03 billion, and “Small Business Saturday” (the latest ‘named’ shopping holiday) brought in $2.82 billion (no name yet, and hence no tracking, for Sunday), all significant rises year-on-year.

On those days, mobile devices accounted for between 46 and 54 percent of all site visits, and between 30 and 37 percent of all sales, said Adobe, the biggest proportion yet.

Interestingly, Adobe said that Small Business Saturday saw the biggest smartphone usage yet, which is somewhat surprising as you might assume that small businesses were more likely to focus on physical store sales (when in actual fact, the state of modern retail rental has led many small business to shift to online-only because rents in high-traffic places are just too high for any business but a big business). It saw smartphone traffic of 46.5% and 56.7% for mobile overall.

As you might expect, Amazon is accounting for the most sales of any single platform. According to Hitwise, the e-commerce giant accounted for 45.1 percent and 54.9 percent of all transactions respectively on Thanksgiving and Black Friday. Hitwise puts the actual numbers at 5.6 million and 7.1 million transactions. We’ve asked for Cyber Monday figures when they come in.

At this moment, Shopify is tracking that there are around $280,000 in sales being made every minute (and in the time I’ve been writing, the number has shot up by about $20,000). As a point of comparison, Shopify noted that at its peak, this year’s Black Friday was generating $1 million in sales each minute.

Top items for purchasing, according to Shopify, are Apparel, Accessories and Housewares (in that order). The “cyber” of Cyber Monday is more related to how you shop than what you shop for: Electronics is the sixth-most-popular category for shopping today, between makeup and food.

Adobe, meanwhile, highlights toys, whose prices are down 18.8 percent since October; computers (discounted 14.7 percent) and TVs (21.1 percent discounted).

Adobe notes that best-selling electronics include many of the usual suspects: Google Chromecast, Apple iPads, Samsung Tablets, Apple AirPods, and Sony Playstation VR. Games and consoles include Super Mario Odyssey, Nintendo Switch and Microsoft Xbox One X.

We’ll update this post as we get more data. If you see anything interesting related to shopping stats online — for example global features rather than those exclusively covering the US market — send it our way to tips@beta.techcrunch.com and we’ll roll that in, too.