"At the very tail end - the week or so leading up to Christmas - we did see... the growth rates slow quite a bit compared with last year," said Dan Hess, a vice-president at comScore Networks. In the 2001 Christmas shopping season, there was a last-minute online spending surge that was not duplicated this year, he added.
Overall, comScore estimated that consumers spent $74bn (£46bn) online shopping in 2002, up 39% on last year. The total includes retail spending as well as spending for online travel accommodation.
In the fourth quarter of 2002, consumers spent about $13.8bn (£8.7bn) online, 27% more than in the same period in 2001, according to comScore. Overall, online retail sales alone amounted to an estimated $43bn (£27bn) in 2002, which is about 5% of the high-street sales.
More consumers shopped online, with about 10 million people a week shopping online in the fourth quarter - a jump of 32% over 2001.
Experienced online shoppers also spent 37% more than in 2001, according to comScore, spending about 50% more than first-timers.
Clothing sales increased, while music CDs, books and consumer electronics - all leading online sellers in the past - had "lacklustre" sales.
Online sales of home and garden items, small appliances and jewellery also increased. "They're bellwethers [that show that] people are considering this is a place to buy a broad range of products," Hess said.