The latest data from the Pew Internet and American Life Project found that two-thirds of the U.S.'s adult Internet users are also online shoppers, corresponding to about 134 million purchasers.
In 2000, only about 47.8 percent of those online had made a purchase, according to Washington, D.C.-based Pew.
Findings from the group's February study also indicates that about 78 percent of online Americans use the Internet to research a product or service before making a purchase.
"E-commerce is completely mainstream now," said Lee Rainie, director of the Pew Internet Project. It's a reality in the lives of two-thirds of all adult Internet users."
According to Pew, about 76 percent of Americans 18 to 49 years old are online as of February. About 58 percent of Americans age 50-64 are, as well.
The implications are far-reaching, Rainie said.
"That is not only important because of the economic consequences it suggests, but also because it represents such a vote of confidence in the online world," he said. "People clearly have found e-retail sites they trust. The worst players in online commerce have either vanished or cleaned up their act."
But Rainie added that e-commerce remains "a drop in the bucket" compared to the overall U.S. retailing market.
"Trillions of dollars are spent by US retail consumers each year and the best estimate is that e-commerce amounts to $100 billion to $130 billion," he said. "E-commerce is certainly less than 5 percent of all U.S. retailing. The 'good news' in that, of course, is that there is still plenty of room to grow."
Meanwhile, across the pond, insiders are expecting a similarly rosy year ahead for U.K. e-tailers. The Interactive Media in Retail Group (IMRG) -- the country's leading e-commerce industry association -- forecasted that some 20 million British Internet users will spend a total of £17 billion ($31 billion) online during 2004.
IMRG Senate membership includes retailing giants such as Tesco, IKEA, BT, easyJet, and RoyalMail and technology vendors WorldPay and Hitwise.
What's more, the group said in its 2004 Senate Annual Statement that within five years, a quarter of all U.K. shopping -- amounting to £80 billion ($146 billion) -- will be handled using the Internet or mobile devices. A further 20 percent of purchases will be influenced by online research, IMRG said.
"Internet shopping will become mass market in 2004, as millions of consumers routinely go online to research and buy every kind of product and service," the group said in a statement.
The IMRG Senate, in its annual report, indicated that U.K. e-tail will grow during the coming years thanks to members' improving commitment to customer satisfaction; new secure payment solutions provided by credit card companies; continuing broadband proliferation; and the emergence of Internet Shopping is Safe (ISIS), an IMRG- and government-sanctioned accreditation program that signifies that a small business' Web site is trustworthy.
IMRG members did highlight challenges that they continue to face, identifying customer retentions strategies as their chief obstacle to overcome during the year, followed by improvements in marketing, statistics-gathering, and fighting fraud.
Christopher Saunders is managing editor of eCommerce-Guide.com.