中国民主化運動
Journalists have frequently been denied entry to the Square on the anniversaries of the massacre. Also, the authorities are known to have detained foreign journalists and increase surveillance of prominent human rights activists during this time of year. Internet searches on "June 4 Tiananmen Square" made within China return censored results or result in temporarily severed server connections. Specific web pages with select keywords are censored while other websites, such as those which support the overseas Chinese democracy movement, are blocked wholesale. The policy is much more stringent with regard to Chinese-language sites than it is with regard to foreign-language ones. Social media censorship is more stringent in the weeks leading up to the anniversaries of the massacre; even oblique references to the protests and seemingly unrelated terms are usually very aggressively patrolled and censored. In January 2006, Google agreed to censor their mainland China site to remove information about Tiananmen and other subjects which are considered sensitive by the authorities. Google withdrew its cooperation on censorship in January 2010.