China may be the most extreme example, but Google says its services are blocked or censored in a quarter of the countries in which it operates.
"Google products - from search and Blogger to YouTube and Google Docs - have been blocked in 25 of the 100 countries where we offer our services," says Rachel Whetstone, vice president for global communications and public affairs.
"In addition, we regularly receive government requests to restrict or remove content from our properties."
Whetstone says the only material the company removes globally from search results is child pornography, some links to copyrighted material, spam, malware, and results containing sensitive personal information such as credit card numbers.
"Specifically, we don’t want to engage in political censorship," she says.
But it's all a different when it comes to Blogger, YouTube, and Picasa Web Albums.
"For example, in Turkey, videos that insult the founder of modern Turkey, Mustafa Ataturk, are illegal. Two years ago, we were notified of such content on YouTube and blocked those videos in Turkey that violated local law," says Whetstone.
"A Turkish court subsequently demanded that we block them globally, which we refused to do, arguing that Turkish law cannot apply outside Turkey."
According to the OpenNet Initiative, 40 countries now actively censor the internet, compared with just a handful in 2002.
Google says that even for search results, it complies with national laws in democratic countries, for example by barring pro-Nazi matierla in Germany.
But Australia looks set to test the company's resolve, with the government pushing for laws to block access to all sorts of material that most would find pretty unobjectionable, such as chatrooms for gay teenagers.