The poll of more than 5,300 mainlanders found that most people who circumvented government internet blocks were well-educated young people aged between 22 and 25.

And two-thirds of the respondents say they go over the Great Firewall every day.

Access to social networking platforms, such as Twitter and Facebook, which have been blocked since the middle of last year, came second as the reason to scale the Great Firewall, and access to foreign news websites that are otherwise banned in China finished third.

About 30 per cent of the respondents admitted their purpose was to visit pornographic sites.

Ng, a Beijing-based blogger who declined to give his age and other personal information because of the sensitivity of the issue, said that his initial motive for doing the survey was business. 'Since the increasing number of mainland internet users are having problems visiting all kinds of overseas websites, I believe there is a huge market for selling wall-scaling services to them,' he said.

According to his survey, 85 per cent of the respondents said they would teach their friends how to scale the wall.

But half of the people said they would accept censorship if the authorities could provide a clearly defined law and be transparent about its enforcement.

Ng admitted the survey should be used only for reference, as the respondents are mainly from several 'micro-blog' sites run by mainland portals and Twitter - an American-based micro-blog service. Its representativeness is therefore limited.

Even so, some mainland internet and political analysts said the survey gave people a first look at the behaviour of mainland wall scalers.

Most of them also pointed out that though mainland authorities had obviously tightened control of the internet after the Beijing Olympic Games ended in August 2008, in the long run the Great Firewall could lose its stranglehold, as such blocking is affecting large numbers of people who need access to overseas online information for their daily work.

'The fact is, the more that people are willing to pay for ways to access the information, the less effect the wall will have,' said Michael Anti, a Beijing-based internet analyst. Ng's survey shows that though more than 70 per cent of the wall scalers are using free proxy tools, others pay for proxy services, such as virtual private networks (VPN) and Secure Shell, which have become more popular among mainland internet users since the government began blocking the free services on a large scale in the past few years.

Wen Yunchao, a Guangzhou-based internet analyst and technician who is also known as Beifeng, said it was impossible for mainland authorities to completely block VPN services, mostly provided by overseas companies, because many multinational corporations and even embassies and consulates on the mainland are using such services.

Wen has calculated that if a VPN service provider rents only five or six overseas-based servers and charges each customer an annual fee of 120 yuan (HK$136), it can make a profit of 50,000 to 60,000 yuan a year - assuming it can find enough buyers.

'All they'll need to do is sell proxy services, and then won't need to do any work at all,' he said, adding that he was optimistic about the future of the mainland's VPN market.

Ng said that after seeing the result of his survey, he decided not to enter the market in the short term, because the service he wanted to launch - a high-speed and stable VPN - would cost 600 yuan a year, too expensive for most mainland users.

But Wen pointed out that Ng should consider not only the respondents to his survey.

'I think most of the respondents already had proxy services, because otherwise many of them could not have had access to the poll, which was posted on several websites blocked by the government,' he said. 'There are many more internet users who are eager to scale the wall but do not know how.

'That will be the future market.'