Yahoo! worst in China

From http://www.theregister.co.uk/2006/06/16/yahoo_china_censor/

Yahoo! worst in China

John Oates / The Register June 16 2006

Yahoo! restricts access to more websites than any other search engine in China.
Lobby group Reporters without Borders tested Yahoo!, Google, MSN and baidu.com. It found that Yahoo! censors its results even more strictly than local portal baidu.com.
The research also found that Microsoft, which claims not to censor its results, returns very similar results to Google, which admits to filtering its content. A search using a subversive word returns 83 per cent pro-government websites on google.cn versus 78 per cent on msn.com. Perform the same search on google.com and only 28 per cent of the results will be pro-Beijing websites.

Censorship on yahoo.cn is almost complete - 97 per cent of sites returned on subversive searches support the Chinese government. In fact, researchers found that searching for "Tibet independence" or "6-4" (4 June is the anniversary of Tiananmen Square) won't just give you shonky results but will get you barred from the site for an hour.
The other search terms used were: Falungong, Tibet Independence, Democracy, Human rights, and press freedom.