Veteran dissident Liu Xiaobo is one of China's most articulate advocates of internet freedom. He is also more affected than most by its absence.

A web search for the characters of Mr Liu's name using Google's Chinese language service in the US, for example, yields more than half a million links to items outlining the liberal views that have thrice landed him in jail and re-education camps. But a decision by Google of the US to censor its new China-based service means the same search there yields a paltry 19,000 web links - and many of those refer to less prominent namesakes.