Facebook, the social networking site which has prompted fears over its users' privacy, has failed in an attempt to keep the personal life of its chief executive private.

A court has ordered that a Harvard-based website should not be forced to take down documents which paint an unflattering picture of Mark Zuckerberg, 23, during his time as a student at the university.

The documents, which include Mr Zuckerberg's handwritten application to Harvard, as well as excerpts from an online diary he wrote, and a letter to the Harvard Administration Board, had been posted by 02138, a website, as part of an article about a lawsuit current being brought against Facebook.

Facebook had requested that the documents, which contain acerbic remarks about Mr Zuckerberg's peers, be taken down.

Facebook, which now has more than 50 million users in the UK, has been criticised for making it too easy for people to post comments, photos, videos, and other material which could come to be embarrassing for them later on.

The site says it gives its users full control over their 'privacy settings', but only last week it was forced to change its plans for a new advertising feature which would have sent details of purchases made by a user elsewhere on the web to their 'friends' on the site without the user's explicit consent.

Last week, 02138, a site given over to Harvard and its alumni, published an article about some fellow students of Mr Zuckerberg's who claim that he stole the idea for Facebook from them while doing some programming for their 'networking' site in 2003 and 2004.

Alongside the article, the site posted some documents that were filed as part of the students' lawsuit.

The documents, which also reportedly give details of Mr Zuckerberg's social security number, his girlfriend's full name, and the address of his parents in New York, were ordered 'sealed' by the judge hearing the case, which is being heard by a federal court in Boston.

But the reporter who wrote the piece said he had obtained them from another court which had also considered the case, and that he had done nothing wrong.

A clerk at the First Circuit Court of Appeals, in Boston, had apparently made a mistake and let him read and copy sealed documents, the reporter told the New York Times.

The editor of 02138, which is not formally associated with Harvard, said that although some of the pages the reporter had obtained were marked 'Confidential', they had been obtained legally, and therefore the site had clearance to publish them.

On Thursday, Facebook asked Douglas Woodlock, of the Federal District Court in Boston, to order that 02138 remove the documents from its site. In a statement the company said: "One reason the court ordered certain documents protection was to prevent exactly what has happened: misusing documents and taking documents out of context to sling mud."

But according to 01238's lawyers, Judge Woodlock turned down Facebook's request late on Friday. The documents were still accessible on the site this morning.

"This is a victory not only for 02138 but for the First Amendment as well," 01238's founder Bom Kim was quoted as saying. "We felt we had an important responsibility to report the story and we hope that we were able to promote greater public understanding of the origins of a powerful and influential web site."

Facebook was not immediately available for comment.