Yahoo takes action against message board users

After a series of high profile lawsuits against users accused of posting malicious rumours to deliberately affect the stock price of companies, Yahoo has taken measures to name and shame malcontentents.

After insisting it would only give user details if forced by subpoena, the Internet company took a U-turn this week - users now have to leave a return email address.

Ralph Averbuch, Yahoo senior producer Europe, said that if the company was alerted to users leaving malicious or defamatory messages it would take action - potentially barring people from the service.

In the most recent case Itex, an online stock trading company, brought an action against 100 "unknown persons" for "intentional inference with economic relationships and civil conspiracy". The company refused to comment on whether its stock price had been affected but said the claims of incompetence were completely unfounded.

Mark O'Conor, IT lawyer at Bird & Bird, said Yahoo's problem could potentially get much worse. "The Internet has been around for a while now and legal principals are being applied - but some of them don't quite fit," he said.

Although Yahoo might want to look as though it is taking a more responsible attitude towards the problem, the company could end up being held responsible for the content on its site. "By showing community spirit and an obligation towards its users, it could be seen as somehow connected with the content and therefore liable," said O'Conor.