This is the first time I’ve ever seen a Firefox Add-on used as a way to make a political statement. An Add-on called China Channel will replicate in Firefox what it’s like to be behind the Great Firewall of China. So if you want to see what it’s like not being able to read about Tibet or other content China doesn’t approve of, this is a good chance. It appears to use proxy servers in China to replicate the experience.
Perhaps the next version will let you toggle between China’s Great Firewall and Australia’s Great Firewall’s (currently in development). I should note Iran and Saudi Arabia are also known for extreme censorship on the internet.