Sohu, Baidu, Microsoft, Google and Yahoo! are all a part of China's Great Firewall. These internet companies filter the world for Chinese net users.They block certain websites, provide limited services and in the case of Yahoo! hand over net user's personal information to Chinese authorities.

The internet is supposedly a bastion of free speech, a tool for sharing information, communicating across borders, across nationalities, without Governments - in China the internet is also a tool for Government surveillance, monitoring and another method of instilling fear and creating self-censorship.

These internet companies have a responsibility to uphold basic human rights principles. They must make policy and practice changes that support the right to freedom of expression and people's privacy. The companies have a real role to play in creating a China that respects freedom of expression, where companies are not complicit in censorship.

Profits do not need to suffer as a result of acting in line with the Universal Declaration of Human Rights. In fact, wouldn't internet users feel safer if they knew which terms and sites were banned, what the ramifications were of posting certain information, what exactly the laws were that could see them imprisoned for their peaceful use of the internet. And safe too, in the knowledge that an internet company would not hand over the user's personal information without at least using existing national laws to challenge the Government request, asking some questions about why it was wanted and what may happen to the individual.

So, can we stop the evil? Yes, we can. Starting in Melbourne on 30 April we will be asking you to help tear down the Great Firewall of China. The walls will travel across Australia for 90 days and we will be sending at least 20,000 individual messages to Sohu, Baidu, Microsoft, Yahoo! and Google letting them know that we want them to use their power and influence to create positive change in China.