[Researchers Dan Wallach and company] say that in their data set about 5 percent of the deletions occur within 8 minutes of posting and around 30 percent within 0 minutes. In total, 90 percent of deletions occur within a day, although at times deletions can occur several days later. Those are impressive numbers given the popularity of the microblogging service. How does Weibo manages this task?
Wallach and co say their data point to a number of hypotheses about what’s going on. Since the highest volume of deletions occur within 5-10 minutes of posting, Weibo must be censoring them in near real time. If an average censor can scan around 50 posts a minute, that would require some 1400 censors at any instant to handle the 70,000 posts pouring in. And if they work 8 hour shifts, that’s a total of 4200 censors on the payroll each day.
But automated censorship tools may reduce the number censors. Caitlin Dewey further unpacks the study:
Among the keywords that could trigger a deletion? “Support Syrian rebels,” “lying of government” and “Beijing rainstorms,” the study reports. (The full list does not look thematically different from a list of terms used to filter the Chinese Internet overall, obtained by the Post in 2006.) The rainstorms caused widespread destruction and anti-government outrage in July 2012, and China officially supports the Syrian regime.