Internet campaigners welcomed a California court ruling that protects service providers and online publishers against defamation lawsuits for posting content written by someone else.

In a written ruling the California Supreme Court overturned a lower court decision, re-affirming that individuals seeking legal redress for comments published online could only sue the original source of the information.

The Electronic Frontier Foundation praised the court decision saying it "reaffirmed the critical rule that the soapbox is not liable for what the speaker has said."

Internet firms and civil liberties groups warned that an earlier California Court of Appeal decision would have made publishers liable for content posted on their websites, stifling freedom of information.

Ann Brick, staff attorney at the American Civil Liberties Union of Northern California said: "Any other ruling would have inevitably made speech on the Internet less free."

The case arose after a hearing in January 2004 in which the Court of Appeal overruled the dismissal of a defamation lawsuit filed against an activist for her re-publication on the Internet of someone else's words.

Rights campaigners argued that the activist should have been granted protection under existing laws passed by Congress.