In half a decade Facebook has become one of the most successful companies on earth but also, a new survey of US consumers has found, one of the least liked.

The level of Facebook’s unpopularity uncovered by the 2011 American Customer Satisfaction Index (ACSI) will make difficult reading for its management on a ranking that placed it 15th from bottom of 227 companies across a variety of sectors.

Facebook is now at 66 on the ACSI index, two better than last year, but some way behind YouTube’s and CNN’s 74, Burger King’s 75, Microsoft’s 78 and Google’s 83. The top performers included Amazon and Unilever on 87, Apple on 86, Lexus on 85, and FoxNews on 82.

“Even with this year’s two-point increase, Facebook continues to register as one of the lowest-scoring companies measured by the ACSI,” said the report.

Below it lies a desert of traditionally-disliked companies such as airlines and mobile communications companies. The only company in a similar business to Facebook that scored as poorly was MySpace, which has plummeted so low it now no longer even registers as even being merely unpopular. It seems to have no measurable profile at all.

None of this would probably matter to Facebook or its users if it weren’t for the looming appearance of Google+, which for the first time offers consumers a competitive choice.

“Google is a company that has traditionally received ACSI scores in the 80s—it is among the highest-rated companies in terms of customer satisfaction. If Google can carry over their customer-centric ethos to Google+, Facebook could have serious competition that has the potential to very quickly erode its market share,” the authors conclude.

Facebook has had a difficult year over privacy issues culminating in an Orwellian plot to use PR firm to smear rival Google, a move that won it few admirers.

In the search engine market there seem to be two winners, Google and Bing., Yahoo, and AOL all appear register lower index scores, reflecting their much smaller market share.

Some of the preferences could be related to politics and image as much customer satisfaction; the more liberal scored a lowly 69 while the sometimes controversial rated a much better 82.

Although it only measures US consumer opinion, the American Customer Satisfaction Index is calculated by ForeSee Results from 70,000 interviews carried out throughout the year.