Even as online sales grow, retailers aren't doing enough to satisfy customers, missing opportunities to transform browsers into buyers, said Larry Freed, president of ForeSee Results and author of the report.

Customer satisfaction, when measured scientifically using the University of Michigan's American Customer Satisfaction Index (ACSI), has proved to be a leading indicator of financial performance and how customers will behave in the future, according to the report.

Of the top 40 online retail sites measured by ForeSee and FGI, four scored 82 or higher on the ACSI's 100-point scale; 82 is considered a superior rating.

Netflix.com was the leader in browser satisfaction, with a score of 85, followed by Amazon.com at 83 and QVC.com and Newegg.com, each at 82, according to the report. Twenty-nine of the 37 companies that were measured this spring and during the 2005 holiday season posted higher customer satisfaction scores in the latest study, according to the report.

When the top 40 sites were compared to their scores a year ago, 24 had a lower rating, and six remained the same, according to the study. Only seven online retailers, led by Chadwicks.com (78), which saw a 6.8 percent jump in satisfaction, managed to raise their scores, Freed said.