Instead of leaving China or bowing to pressure from government censors, Google came up with a third option: It's maintaining research and development and sales staff in China, but when searchers in China bring up its Web site, they are rerouted from Google.cn to Google.hk.
Although now part of China, the handover agreement from British rule allows [Hong Kong] to operate as a semi-autonomous region until 2047 -- the "one country, two systems" approach. The city has a free press and tolerates political dissent.
As such, Google is not required to filter search results there. However, the Chinese government does censor results on Google.hk - through a system known as "The Great Firewall." Searches on prohibited topics, such as "Tiananmen Square massacre" result in brief loss of access to Google.hk, accompanied by a message that the "connection to the server was reset..."
And Google's opinion of the Chinese censors reaching into Hong Kong? CNN.com reports:
Google said if the government blocks access from mainland China to its Hong Kong search site, it may further reduce its presence there.