Customer satisfaction with e-commerce dropped slightly in 2008 and researchers think that the economy is at least partly to blame.

The University of Michigan and ForeSee Results released their annual American Customer Satisfaction Index (ACSI) on Tuesday. It rated e-commerce sites at 80 points on a scale of 0 to 100. That's down from 81.6 the previous year.

Satisfaction with online brokerages decreased from 79 points in 3007 to 74 points last year, with TD Ameritrade suffering the biggest drop from 80 points in 2007 to 71 points in 2008, according to the ACSI. Researchers said that likely reflected decreased trust in financial services.

Online travel sites held steady with an overall score of 75 points in 2007 and 2008, according to the report. Expedia scored highest at 77 points, up from 75 points in 2007. Travelocity ranked second with 75 points, up from 73 points in 2007, and Orbitz ranked third at 74 points, up from 73 points in 2007.

Online retailers fared better than other ecommerce sites, scoring 82 points, down slightly from 83 points in 2007. EBay scored lowest among online retailers at 78 points, which marked a low for the online auction site in the nine years since the ACSI was established.

Newegg, a consumer electronics site, had the highest customer satisfaction rating (88 points) among online retailers, the ACSI found. That knocked Amazon out of first place into second, with 86 points, down slightly from 88 points in 2007. Netflix ranked third, with 85 points, up one point from the previous year.

Researchers also found that almost all e-commerce sectors fared better than brick-and-mortar businesses.

Learn more about Web 2.0 at TechWeb's Web 2.0 Expo, March 31-April 3. Join us. (registration required).