Defiant cyber surfers on the mainland can run Web sites and circumvent police control by using overseas service providers. The Web site run by Huang Qi - 6-4tianwang.com - operates via a US-based Internet service provider. This means its content can be updated either on the mainland or in the United States and mainland surfers can easily slip through filters set by mainland cyber police. The site was still accessible yesterday and a statement about Mr Huang's arrest - apparently by its operators in the US - was posted on its homepage last night. The chat room also remained open. When the authorities try to block sites like 6-4tianwang.com, surfers can still manage to access them by using overseas or other methods. The Web site was launched in June last year as the first in China dedicated to helping people find relatives abducted by traffickers. The case of 6-4tianwang.com highlights the difficulties faced by mainland authorities in policing the Internet. Cyber police have issued numerous regulations to tighten their grip on the Internet. And the State Council recently set up a special division under its Information Office to monitor news on the Web. But there are plenty of indirect routes to post messages on the net and there are always ways to access them. Examples include discussions about the 1989 Tiananmen Square crackdown - a subject considered taboo by the authorities. No matter how fast Web masters move to delete messages posted on their chat rooms, surfers can always shift to other chat rooms to continue their discussions. It was not the first time Mr Huang had been in trouble with the authorities. The Web site was shut down by police in March over reports concerning the human rights of Chinese labourers working overseas. It was reopened in April apparently with the help of a US-based Chinese group. Undeterred, Mr Huang went further late last month and began to post news related to the 1989 democracy movement on the Web site, until his arrest on Saturday.