US District Judge Douglas Woodlock told Cameron Winklevoss, Tyler Winklevoss and Divya Narendra they must produce evidence that they hired Facebook founder Mark Zuckerberg to work on Harvard Connection.
"Dorm room chitchat does not make a contract, so I want to see it," Judge Woodlock said in court as the case began yesterday.
The legal suit was originally filed in September 2004, but was dismissed on a technicality and the trio had to refile.
Facebook spokeswoman Brandee Barker said that the company was pleased with the outcome of the initial hearing.
"We continue to disagree with the allegations that Mark Zuckerberg stole any ideas or code to build Facebook," she said.
The three complainants now run social networking website ConnectU, which has around 100,000 users compared with Facebook's 32 million.
Zuckerberg filed a separate lawsuit in a Californian court in 2005 alleging that ConnectU hired hackers to steal thousands of email addresses from Facebook.
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