A team at Carnegie Mellon University has analysed tens of millions of Sina Weibo posts, uncovering patterns in China’s “soft censorship”—the deletion of existing posts, as opposed to the “hard censorship” of pre-emptive blocking. The project was conceived when researcher David Bamman noticed the mass deletion of Jiang Zemin death rumours last summer. From New Scientist:
“What was … interesting was that messages you’d expect to have been deleted all the time – like mentions of the Falun Gong [spiritual movement] or the dissident and artist Ai Weiwei – were not done so every time. It would seem to suggest that there is no automatic, blanket deletion going on,” says Bamman. Rather it points to a high level of human involvement and a nuanced approach.
The censorship mechanism is also agile – able to turn its attention to troublespots on demand. “This is the most surprising thing that we saw,” says Bamman. “In Tibet there was an overall deletion rate of 53 per cent – against 12 per cent in Beijing and 11 per cent in Shanghai ….”
Two other areas with relatively high minority populations, Qinghai and Ningxia, also suffered from particularly high rates of deletion according to Carnegie Mellon News, where the researchers’ methodology is explained in greater detail:
To study this “soft” censorship, the CMU team analyzed almost 57 million messages posted on Sina Weibo, a domestic Chinese microblog site similar to Twitter that has more than 200 million users. They collected samples of weibos from June 27 to Sept. 30, 2011, using an application programming interface (API) that Sina Weibo provides to developers so they can build related services.
Using the same API, they later checked a random subset of weibos to see if they still existed and another subset that included terms known to be politically sensitive. If a weibo was deleted, Sina would return what the researchers came to regard as an ominous message: “target weibo does not exist.”
In late June and early July, for instance, rumors began circulating of the death of Jiang Zemin …. On July 6, at the height of the rumor, 64 of 83 messages containing his name were deleted; on July 7, 29 of 31 such messages were deleted.