Making Internet intermediaries liable for lese-majeste postings is like making restaurant owners liable for what diners say at the dining table, Internet expert Danny O'Brien said yesterday in written testimony to the Thai court trying webmaster Chiranuch Premchaiporn.

"It would be structurally equivalent to making the telephone company liable for any statements made by its subscribers over the telephone," O'Brien said.

"By holding an intermediary liable for the actions of its users, this case could set a dangerous precedent and have a significant long-term impact on Thailand's economy," he warned.

"It could also end up denying Thai Internet users access to many of the online services they use everyday," said O'Brien, who works for the New York-based Committee to Protect Journalists.

Online marketplaces and Web forums are critical components of the Internet today, he said.

The trial of Chiranuch - the director of the prachatai.com online newspaper who was charged under the Computer Crimes Act for not removing alleged lese majeste contents posted by others from its webboard quickly enough - has been postponed to February.

The court cited the flooding as affecting a presiding judge's home and a tight schedule. Chiranuch faces a maximum 20 years' imprisonment if found guilty.

O'Brien, a defence witness, argued that Chiranuch should not be considered guilty as the Internet operates differently from other media in requiring the "automated transmission and re-transmission of content by many intermediaries without their interference or close examination".

The international standard of intermediary liability has traditionally been reserved for "possession and/or distribution of unlawful material, with distribution assumed to be closely associated with deliberate content", he said.

All communications are imported and exported at great speed through many unrelated intermediaries, he said.

"If all these intermediaries had a responsibility to check the legality of what they relayed, the entire Internet would grind to a halt," he said.

Section 230 of the Communications Decency Act of the United States was also cited.

"No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another content provider."

International law places no "pre-emptive obligation" on the intermediaries to monitor content for illicit activity, he added.