In 2000, Nielsen Norman Group conducted usability tests of 20 B2C e-commerce sites. A total of 64 users participated: 39 from the United States and 25 from Denmark, giving us data about both domestic users (19 of 20 sites were American) and overseas users. Users ranged in age from their 20s to their 50s. All users had previously shopped online and most had made purchases. However, we screened out participants who had technical knowledge of the Web.
A highly experienced facilitator sat in the room with each user, providing instructions and taking notes. We asked users to think aloud as they worked.
After extensive analysis of this data, Nielsen Norman Group has developed and published 222 design guidelines, addressing the following aspects of e-commerce user experience: category pages; international users; product pages; checkout and registration; search; selling strategies; and trust. The report also includes a more detailed description of the methodology.
The 222 guidelines for e-commerce usability can be downloaded from www.nngroup.com/reports/ecommerce.