Concerns about privacy, user interface changes and advertising spurred Facebook users to claim that they aren't happy with the Website, according to the 2010 American Customer Satisfaction Index E-Business Report.
Despite having 500 million users, Facebook scored 64 on ACSI's satisfaction scale of 100, ranking it lower than IRS e-filers, said ForeSee Results, which partnered with ASCI on the survey July 20.
Facebook, which lets users friend folks and "like" comments, content and fan pages, ranks with airlines and cable companies in the bottom 5 percent of all the private companies ASCI measured.
ForeSee President and CEO Larry Freed described a paradox in Facebook's failure to satisfy users despite its undeniably massive base of a half billion users.
"Facebook is a phenomenal success, so we were not expecting to see it score so poorly with consumers," Freed said. (PDF) "At the same time, our research shows that privacy concerns, frequent changes to the Website, and commercialization and advertising adversely affect the consumer experience."
Facebook late in 2009 sparked complaints when it redesigned its home page. Freed contrasted Facebook's evolution with that of the nonprofit Wikipedia, which offers no advertising and has sported only incremental user interface changes over the years.
Facebook also regularly triggers privacy concerns, most recently with its instant personalization, universal "like" button and social plug-ins. And still the Website is gaining new users at a pace of 200 million per year.
Facebook users are as picky about how their social information is used and consumed as they are passionate about sharing information with friends, family and colleagues.
Wikipedia led the social media category, which ASCI considered for the first time, with a score of 77. YouTube scored a 73, while MySpace notched a score of 63, or one behind Facebook.
Twitter, which has more than 100 million users, was not included because too many of its users access Twitter through third-party applications rather than the Twitter.com site.
Meanwhile, Google fell 7 percent in the search engine and portal industry category, but led with a score of 80, surpassed only by "all others."
Microsoft's Bing search engine scored 77, followed by Yahoo with 76, AOL with 74 and Ask.com with 73. Freed said Bing's score is impressive considering it was the first time it had been counted.
See the ASCI graphs at Search Engine Land here.