Feeds

Gone in 30 minutes: Chinese tweets purged by army of censors

New report claims thousands of censors could be working for Sina Weibo

Choosing a cloud hosting partner with confidence

The murky world of online self-censorship in China has come under the spotlight again in a new report which estimates that most post deletions on the Twitter-like Sina Weibo occur within the first 30 minutes of appearing.

The Velocity of Censorship: High-Fidelity Detection of Microblog Post Deletions, was researched by academics at Bowdoin College, Rice University and the University of New Mexico alongside independent researcher Tao Zhu(h/t MIT Technology Review).

Sina claims its service has over 500 million users, but for the purposes of this research the team concentrated on the posts of around 3,500 “sensitive” users with a track record of censorship.

Developing a system “which collects removed posts on targeted users in almost real time”, the researchers found that roughly 12 per cent of posts were deleted over the 15 day monitoring period – which amounts to more than 4,500 every day.

The research included the following observation(PDF):

Our research found that deletions happen most heavily in the first hour after a post has been made. Especially for original posts that are not reposts, most deletions occur within 5-30 minutes, accounting for 25 per cent of the total deletions of such posts. Nearly 90 per cent of the deletions of such posts happen within the first 24 hours of the post.

To enable such speedy censorship, the report claims a mixture of technical and non-technical filtering is used, with potentially thousands of staff employed to eyeball content, as per the following hypothesis:

The deletions happen most heavily for a regular post within 5 to 10 minutes of it being posted. Suppose an efficient worker can read 50 posts per minute, including the reposts and figures included in the posts. Then to read Weibo’s full 70,000 new posts in one minute, 1,400 workers working at the same time would be needed. If these workers only worked in 8 hour shifts, 4,200 workers would then be required.

Proactive keyword filtering blocks certain posts before they have gone live, or holds them for human review, while a range of retroactive mechanisms including backwards keyword and repost searches, public timeline filtering and monitoring of specific censorship-prone individuals were also highlighted in the report.

The research also hypothesises that the censors work “relatively independently, in a distributed fashion”, with activity only really dipping between around 1-7am and again slightly at 7pm – which the report authors claim could be due to the national TV news programme broadcast at that time.

Although the report casts new light on the speed and accuracy of China’s web censors, it doesn’t explain why more isn’t done to block potentially illegal content before it is even posted.

One possible answer came from Sina Weibo manager @geniune_Yu_Yang (正版于洋), who – apparently frustrated by user anger directed at the company’s army of censors - wrote an illuminating post of his own back in January.

He effectively argued that Sina is trying to work around the strict regulations forced upon it by government, by at least letting users see and disseminate their content for a few minutes before it is deleted.

He wrote:

You can see the messages before they are deleted, right? You still have your account functioning, right? You are all experienced netizens, you know that the technology allows us to delete messages in a second. Please think carefully on this.

Now, there is no way of proving whether this manager was engaging in a crafty piece of well-timed PR or if there’s some truth to his claims.

Somewhat ironically, his post too was deleted, which illustrates perfectly the central problem with censorship of this kind: there's no way of telling whether a piece of content is deleted because it was true, or because it wasn't. ®

Beginner's guide to SSL certificates

More from The Register

next story
Facebook pays INFINITELY MORE UK corp tax than in 2012
Thanks for the £3k, Zuck. Doh! you're IN CREDIT. Guess not
Happiness economics is bollocks. Oh, UK.gov just adopted it? Er ...
Opportunity doesn't knock; it costs us instead
YARR! Pirates walk the plank: DMCA magnets sink in Google results
Spaffing copyrighted stuff over the web? No search ranking for you
In the next four weeks, 100 people will decide the future of the web
While America tucks into Thanksgiving turkey, the world will be taking over the net
Microsoft EU warns: If you have ties to the US, Feds can get your data
European corps can't afford to get complacent while American Big Biz battles Uncle Sam
Don't bother telling people if you lose their data, say Euro bods
You read that right – with the proviso that it's encrypted
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.