The annual e-business report for the American Consumer Satisfaction Index found that the Mark Zuckerberg-founded site faced the biggest decline of measured companies, with an 8 percent drop from last year. Facebook is now rated at 61 on a 100-point scale . That's a record low for Facebook, placing it as one of the bottom five companies in consumer satisfaction, among 230 measured.

The survey by the Ann Arbor, Michigan-based ACSI was conducted with customer experience analytics firm ForeSee.

Jeers for Timeline

The dissatisfaction seems to stem from Facebook's Timeline feature, which is being phased in to all user profiles. Timeline is intended to make pages seem more like a curriculum vitae and spur people to reminisce about older updates and photos. Indeed, the ACSI report concluded that, "the most frequent complaints about Facebook are changes to its user interface, most recently the introduction of the Timeline feature."

Adding insult to Facebook's injury, Google+, the fledgling rival network, scored 78 percent in satisfaction for its rookie year in the survey, which was based on interviews with 70,000 consumers. That result was attributed to an absence of traditional advertising and what is seen as a superior mobile product.

"Facebook and Google+ are competing on two critical fronts: customer experience and market penetration," said Larry Freed, President and CEO of ForeSee. "Google+ handily wins the former [market penetration], and Facebook handily wins the latter [customer experience], for now."

Pinterest (69), LinkedIn (63), and Twitter.com (64) all scored higher than Facebook, and YouTube fared much better, with a 73 rating.

Wikipedia tied Google+ at 78, the third straight year it showed the happiest users.

Griping about changes has become a part of Facebook's culture, but so far the company hasn't seen any shift in its 800 million-plus user accounts. Perhaps the lack of drop-off is due to the fact that the service is free and dissatisfied users can simply log off and not return, rather than calling up to demand a refund and close their accounts.

But as the now-public company struggles to stabilize its stock price with revenue enhancements, the griping level can't easily be dismissed.

Afraid To Leave?

"Customer satisfaction always matters," said digital media expert Rebecca Lieb of the Altimeter Group. "Facebook's advantage in retaining users isn't because it's free, but because its user base is so vast. Leave Facebook and you leave your friends and network behind."

Foresee's CEO Larry Freed said, "It's worth asking how much customer satisfaction matters for Facebook, given its unrivaled 800 million-user base. But I expect Google to leverage its multiple properties and mobile capabilities to attract users at a rapid pace. If Facebook doesn't feel the pressure to improve customer satisfaction now, that may soon change."

Facebook isn't alone in taking a popularity nose-dive. The expanded social media category overall is down 1.4 percent to 69.

Consumers weren't as thrilled with their search portals as last year, either: The overall category dropped 1.3 percent, but still tops the e-business sector by a large margin at 79.

Among search portals, Google grabbed the highest rating for satisfication with 82, closely followed by Microsoft 's Bing (81), Ask.com (80) and Microsoft's MSN (78), Yahoo! (78), and AOL (74).

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