martijnd writes: "South Korean Internet users are finding that leading a product boycott in cyberspace can lead to a real-world travel ban and prosecution. Following the mass protests against beef in recent weeks many netizens had called for a boycott of products promoted by Korea's main conservative papers. The boycott was so effective that both the newspapers and their advertisers felt the pinch, with some companies going under. Now prosecutors are trawling through website logs to match IP addresses with real world identities to find the boycott leaders and bulleting board admins. So far twenty South Koreans have been banned from leaving the country."