Other top brands in the study were eBay with 223.5 million visitors (16.2%), China’s Alibaba.com with 156.8 million visitors (11.3%), Apple.com with 134 million visitors (10%) and Rakuten with 57.8 million visitors (4.2%).

                                             Amazon, eBay, Alibaba have largest global audiences

Geographical composition of Internet sites for retail and auction sites

Amazon and Apple worldwide sites showed more globally distributed audiences compared to most other brands in the study. Amazon attracted 35.4% of its visitors from North America, while Europe contributed 31.8% and Asia Pacific 24.1%.

Apple.com had 32% of its visitors from North America, while Europe contributed 29.6% and Asia Pacific 24.9%.

Visitors to China’s Alibaba.com and Japan’s Rakuten were mainly from the Asia Pacific region, at 85.7% and 72.7% respectively.

Of the 10 selected sites, MercadoLibre showed the strongest concentration of visitors from a single region, with 93.3% of its visitors from Latin America where it ranked as the top retail player in the region.

German retail site, Otto Gruppe, also had a heavy single region concentration with Europe accounting for 92.3% of its audience.

Wal-Mart’s and Hewlett Packard’s visitors’ concentration were in North America at 83.4% and 45.1% respectively.

Gian Fulgoni, comScore co-founder and chairman (pictured right), said that while retail e-commerce had  grown to become a US$150+ billion annual industry in the U.S. it still presents enormous upside opportunity across much of the globe.

“Technology has changed the way consumers behave, and increasingly they are opting for the convenience and pricing advantages offered by the online channel. Several global retail brands have already capitalised on this global consumer trend, and many other retailers are sure to pursue their share of the pie,” he added.

• Charts: Statistics exclude visitation from public computers such as Internet cafes or access from mobile phones or PDAs.