The subtitle of today’s paper is
On Measuring Censors’ Resources and Motivations. It’s a position paper, whose goal is to get other researchers to start considering how economic constraints might affect the much-hypothesized
arms race or
tit-for-tat behavior of censors and people reacting to censorship: as they say,
[…] the censor and censored have some level of motivation to accomplish various goals, some limited amount of resources to expend, and real-time deadlines that are due to the timeliness of the information that is being spread.
They back up their position by presenting a few pilot studies, of which the most compelling is the investigation of keyword censorship on Weibo (a Chinese microblogging service). They observe that searches are much more aggressively keyword-censored than posts—that is, for
many examples of known-censored keywords, one is permitted to make a post on Weibo containing that keyword, but searches for that keyword will produce either no results or very few results. (They don’t say whether unrelated searches will turn up posts containing censored keywords.) They also observe that, for some keywords that are not permitted to be posted, the server only bothers checking for variations on the keyword if the user making the post has previously tried to post the literal keyword. (Again, the exact scope of the phenomenon is unclear—does an attempt to post any blocked keyword make the server check more aggressively for variations on all blocked keywords, or just that one? How long does this escalation last?) And finally, whoever is maintaining the keyword blacklists at Weibo seems to care most about controlling the news cycle: terms associated with breaking news that the government does not like are immediately added to the blacklist, and removed again just as quickly when the event falls out of the news cycle or is resolved positively. They give detailed information about this phenomenon for one news item, the Wukan incident, and cite several other keywords that seem to have been treated the same.
They compare Weibo’s behavior to similar keyword censorship by chat programs popular in China, where the same patterns appear, but whoever is maintaining the lists is sloppier and slower about it. This is clear evidence that the lists are not maintained centrally (by some government agency) and they suggest that many companies are not trying very hard:
At times, we often suspected that a keyword blacklist was being typed up by an over-worked college intern who was given vague instructions to filter out anything that might be against the law.
Sadly, I haven’t seen much in the way of people stepping up to the challenge presented, designing experiments to probe the economics of censorship. You can see similar data points in other studies of China    (it is still the case, as far as I know, that ignoring spurious TCP RST packets is sufficient to evade several aspects of the
Great Firewall), and in reports from other countries. It is telling, for instance, that Pakistani censors did not bother to update their blacklist of porn sites to keep up with a shift in viewing habits.  George Danezis has been talking about the economics of anonymity and surveillance for quite some time now   but that’s not quite the same thing. I mentioned above some obvious follow-on research just for Weibo, and I don’t think anyone’s done that. Please tell me if I’ve missed something.