It looks as if Google and China were not able to come to an agreement.
The Chinese government maintains that unless Google exercises self-censorship — or as Beijing says, “adhere to the laws of China” — it would not be allowed to continue to operate in China.
Google said it would only operate in China if it could operate freely.
So now Google is sending all searches on google.cn to its Hong Kong site. (And please remember that Hong Kong, while part of China, has civil right and liberties, including freedom of speech and press.)