SAN JOSE, CA: Cyber Monday was the largest online sales day ever in the US, according to figures from Adobe which said that almost $3bn had been spent.

The $2.98bn total marked a 12% increase on 2014 and boosted online sales over the whole Thanksgiving weekend to $11bn, a 15% year-on-year rise.

And in a blurring of categories, brick-and-click retailers saw the strongest growth in sales at 18%.

Adobe's figures were based on analysis of aggregated and anonymous data from more than 125m visits to 4,500 retail websites on Cyber Monday; Adobe claims to measure 80% of all online transactions from the top 100 US retailers.

"Online traffic was so astronomical that several retailers experienced temporary outages and slow checkouts, but that didn't stall consumer spending," said Tamara Gaffney, principal analyst at Adobe Digital Index.

Digiday highlighted the frustration of shoppers at Target, who experienced delays in loading the website and then found themselves in line for popular items – tartly noting that "the point of online shopping is to avoid lines".

A Target spokeswoman said volume had been twice as high as its busiest day ever and that as the website had seen spikes in traffic so some visitors were placed in a queue.

Mobile devices accounted for almost half (49%) of shopping visits, Adobe reported, split 38:11 between smartphones and tablets. And with significant sales volumes being reported as early as 10am ET, it suggested many consumers were shopping from their phones in bed or during their commute.

But they were being used for smaller value purchases, as, together, they made up 28% of online sales. In all, Adobe attributed $514m of the day's sales to mobile, including $313m on from smartphones (with $205m coming via iPhones and $107m via Android) and $201m from tablets ($170m via iPad, $28m via Android).

A separate analysis by IBM predicted that Cyber Monday online sales would be 18% up on last year.

Data sourced from Adobe, IBM, Digiday, Reuters: additional content by Warc staff