Although the 1982 constitution guarantees freedom of speech, the Chinese government often uses the subversion of state power and the protection of state secret clause to imprison those who are critical of the government. The government is also heavily involved in censoring news through the Propaganda Department of the Communist Party of China, even though no state law explicitly gives it such authority.
The Chinese government promised to issue permits allowing people to protest in 'protest parks' during the 2008 Summer Olympics in Beijing, but a majority of the applications were withdrawn, suspended, or vetoed, and the police detained some of the people who applied. References to certain controversial events and political movements are blocked on the Internet and in many publications. Chinese law forbids the advocacy of independence for any part of its territory, as well as public challenge to CPC domination of the government of China. An unauthorized protest during the Olympics by seven foreign activists at the Chinese Ethnic Culture Park, demanding Tibetan independence and blocking the park's entrance, was cleared and the protesters deported.
Foreign internet search engines including Microsoft Bing!, Yahoo!, Google Search China have come under criticism for aiding in these practices, including banning the word "democracy" from its chat rooms in China. Yahoo! in particular, stated that it will not protect the privacy and confidentiality of its Chinese customers from the authorities. In 2005 reporter Shi Tao was sentenced to imprisonment for 10 years for releasing an internal Communist Party document to an overseas Chinese democracy site after Yahoo! China provided his personal emails and IP addresses to the Chinese government. Skype president Josh Silverman said it was "common knowledge" that TOM had "established procedures to... block instant messages containing certain words deemed offensive by the Chinese authorities.