This month, the history department at Middlebury College, a small private institution in New England, voted to ban students from citing Wikpedia in academic work. Other us academic institutes also forbid students from using Wikipedia as their central source.

But a search of court decisions by the New York Times showed up that more than 100 us court rulings have cited the online encyclopedia since 2004, including 13 from the circuit court of appeals, one rung beneath the supreme court.

In a 2005 case before the Tennessee court of appeals, worth hundreds of thousands of dollars, the site was used to help define the meaning of the word "beverage'. It was also cited recently in a federal district court in Florida to offer background on the term "booty music', the New York Times said.

In one instance cited by the newspaper, a decision from a Chicago appeals court cited Wikipedia in a drugs case, even though the judge, Richard Posner, had first-hand experience of its unreliability. One entry had said the conservative commentator Ann Coulter had been his law clerk. Posner has never met her.