Wikipedia has been caught up in a defamation case after a New Jersey literary agent received an unflattering entry in the online encyclopaedia.

Barbera Bauer alleged that Wikipedia and its users defamed her when they wrote that she was the "dumbest of the twenty worst" literary agents. Users also claimed that Bauer had "no documented sales at all".

Bauer has filed cases against the users who posted the entries and Wikipedia itself. However, Wikipedia argues that it is protected from litigation.

The site claims that the entries are considered to be protected speech, and therefore fall under the protection of the First Amendment which guarantees freedom of expression.

The site also claims protection under Section 230 of the US Communications Decency Act which protects website operators from legal action over statements made by individual users.

"We provide a platform through Wikipedia for smart citizens to give their knowledge back to a larger culture," said Wikimedia general counsel Mike Godwin. "Our ability to offer citizens that platform is at stake in this case."

Wikipedia is being aided in the case by the Electronic Frontier Foundation (EFF), and both groups filed a motion on 1 May asking for the suit to be dismissed.

"Wikipedia continues to be a tremendous resource for people around the globe, " said EFF senior staff attorney Matt Zimmerman.

"Without strong liability protection, it would be difficult for Wikipedia to continue to provide a platform for user-created content."