When Barack Obama visited China in 2009, the American leader made it a point to publicly declare himself "a big supporter of noncensorship" and said criticism made him a better president.

"I think that the more freely information flows, the stronger the society becomes, because then citizens of countries around the world can hold their own governments accountable," Obama said. "They can begin to think for themselves."

Implicit in his remarks was the assumption that Chinese censors try to stamp out criticisms of the government and the Communist Party.