Amid Censorship, China's Tiananmen Crackdown is Remembered Online CNN / Getty Images A lone demonstrator stands down a column of tanks June 5, 1989 at the entrance to Tiananmen Square in Beijing. The incident took place on the morning after Chinese troops fired upon pro-democracy students who had been protesting in the square since April 15, 1989. In the years immediately following 1989, the anniversary of the deadly June 4 crackdown on demonstrators in Beijing was marked by smaller memorial protests. At universities in the northwest of the city, students would distribute leaflets, sing the Internationale and break bottles in a show of disrespect to the then-paramount leader Deng Xiaoping, whose given name is a homophone for "little bottle." In 1992, a protester unfurled a banner in Tiananmen Square itself before being dragged away by police. But such public displays have grown rare. This year, on the 23rd anniversary of the crackdown by troops that killed hundreds, possibly thousands of protesters, the anniversary was marked online, on services like Facebook and the Sina Weibo microblog, and possibly even by the Shanghai Composite index. The benchmark began the day at 2,346.98, which read backwards gives 89.64, the year, month and date of the Beijing massacre. As if to reinforce the point, the index dropped by 64.89 points Monday. There was no immediate official explanation for the historically symbolic numbers. "This opening level is normal," an employee of the Shanghai exchange's media department told the Wall Street Journal. Opening levels are decided by appropriate regulations and today's opening level was normal. The Shanghai exchange has long been seen as a hub of insider trading and market manipulation, but this is the first time it may have been tweaked for political symbolism. The Shanghai index numbers are likely a random accident, Reuters reported. Regardless, "Shanghai stock market" joined a long list of search terms banned on Sina Weibo, the Chinese Twitter-like microblog service. Other banned search terms include "64," as the Tiananmen crackdown is known in Chinese, "Tiananmen," and even the Chinese word for "today." The candle emoticon, used to express mourning, was also disabled from the service, as were searches for the Chinese characters for "candle." So a few Sina Weibo users resorted to typing the English word "candle." The popular service's censors were busy deleted any messages even remotely connected to the massacre, but a few cryptic references survived. One message reposted more than 500 times Monday discussed the 228 Incident, when Chiang Kai-shek's Kuomintang killed thousands of civilians in Taiwan's capital of Taipei in 1947. The Kuomintang ruled much of China for two decades before losing a civil war with Mao's Communist Party in 1949, forcing the remainder of Chiang's armies to retreat to Taiwan. In 1995, as part of a process of ending its autocratic rule over the island, the Kuomintang apologized for the 228 crackdown. "The Kuomintang had the courage to overturn its decision," wrote one person on Weibo, a message meant as much for a Communist Party that has refused to address its 1989 decision that the Tiananmen protests were a "counterrevolutionary riot." The specter of Tiananmen censorship also spread to Hong Kong, the semi-autonomous Chinese city where the 1989 crackdown is remembered in annual vigils. On Friday afternoon about 10 political activists including Legislative Council member Leung Kwok-hung saw their Facebook accounts disabled, says Charles Mok, chair of the Hong Kong branch of the Internet Society. Mok says that he was able to get in touch with a Facebook representative from the company's Washington, D.C. office and the accounts were restored by Friday evening. The social networking giant didn't offer a reason for the account closures, Mok says, though activists in Hong Kong suspect it could have been due to false complaints filed in an attempt to thwart organizing ahead of Hong Kong's June 4 memorial vigil.