Known Unknowns: An Analysis of Twitter Censorship in Turkey Rima S. Tanash Zhouhan Chen Tanmay Thakur Rice University Rice University University of Houston 6100 Main St. 6100 Main St. 4800 Calhoun Rd. Houston, TX 77005 Houston, TX, 77005 Houston, TX, 77004 [email protected] [email protected] [email protected] Dan S. Wallach Devika Subramanian Rice University Rice University 6100 Main St. 6100 Main St. Houston, TX, 77005 Houston, TX, 77005 [email protected] [email protected] ABSTRACT a specific country [28]. Once Twitter receives such a request, it Twitter, widely used around the world, has a standard interface somehow determines whether the request is lawful and then with- for government agencies to request that individual tweets or even holds the tweet in question in that specific country, while still allow- whole accounts be censored. Twitter, in turn, discloses country-by- ing it to be visible elsewhere. Twitter claimed that this policy was a country statistics about this censorship in its transparency reports business decision that allowed Twitter to exist in parts of the world ff as well as reporting specific incidents of censorship to the Chilling that have di erent ideas of freedom of expression, and that this pol- ff Effects web site. Twitter identifies Turkey as the country issuing icy will prevent locally o ensive content [29]. The policy received the largest number of censorship requests, so we focused our at- criticism that it was nothing more than a form of government cen- tention there. Collecting over 20 million Turkish tweets from late sorship and a threat to freedom of speech [15]. Unsurprisingly, 2014 to early 2015, we discovered over a quarter million censored trending hashtags like #TwitterCensored and #twitterblackout fol- tweets—two orders of magnitude larger than what Twitter itself lowed this announcement, where many users expressed their out- reports. We applied standard machine learning / clustering tech- rage. Notably, Twitter also announced a partnership with Chilling ff niques, and found the vast bulk of censored tweets contained po- E ects to publish withheld content “unless they are legally prohib- litical content, often critical of the Turkish government. Our work ited from doing so” [28]. Twitter also notes, in their “Withhold- establishes that Twitter radically under-reports censored tweets in ing Transparency Reports” that the reported data is neither 100% Turkey, raising the possibility that similar trends hold for censored comprehensive nor complete. For example, the Politwoops web- tweets from other countries as well. We also discuss the relative site, dedicated to collect deleted tweets from politicians—often a ease of working around Twitter’s censorship mechanisms, although source of raw and embarrassing statements—announced that Twit- we can not easily measure how many users take such steps. ter disabled their API feed on June 4, 2015. Twitter claimed that the company violated their developer agreement [14]. Politicians delet- ing their own tweets is obviously not the same thing as a country 1. INTRODUCTION censoring its citizens, but all the same, Twitter has demonstrated Twitter, the popular microblogging platform, plays an essential that it is opposed to external organizations displaying content that role for communicating news and current events among profes- is not visible on Twitter itself. sional reporters, human-rights activists, and oppressed citizens across Given this, the research question is easy to pose: how much cen- the globe. More notably, Twitter was widely used to disseminate sorship is really happening on Twitter? How much is not being news and opinion during a series of uprisings in the Middle East, reported to Chilling Effects? How much is not being reported on also known as the Arab Spring, resulting in the overthrow of dic- Twitter’s withholding transparency disclosures? And can we de- tatorships in Egypt, Tunisia, Libya [31][34], and the Taksim Gezi termine anything about the machinery behind the censorship? Are Park protests in Turkey on May 2013 [30]. tweets being withheld one by one, based on individual requests to On January 27, 2012, Twitter announced a new censorship policy Twitter by foreign governments, or are they being withheld in large known as “Country-Withheld Content” by which Twitter enabled groups, perhaps based on hashtags or other keywords? We sus- governments and their representatives to formally request that Twit- pect that there is undisclosed censorship on Twitter. We just do not ter withhold tweets and/or whole accounts within the boundaries of know the depth of the unknowns. Permission to make digital or hard copies of all or part of this work for personal or 2. RELATED WORK classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full cita- Chen et al. described that in recent years, social media has risen tion on the first page. Copyrights for components of this work owned by others than in prominence in many countries. In China, social media such ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or re- as Weibo and Renren plays an important role as a platform for publish, to post on servers or to redistribute to lists, requires prior specific permission breaking news and political commentary outside of the confines of and/or a fee. Request permissions from [email protected]. state-controlled news media. However, like all websites in China, WPES’15, October 12, 2015, Denver, Colorado, USA. c 2015 ACM. ISBN 978-1-4503-3820-2/15/10 ...$15.00. Chinese social media is subject to censorship. The magnitude of DOI: http://dx.doi.org/10.1145/2808138.2808147. censorship varies dramatically across topics, with 82% of posts in 11 Number Number some topics being censored. The paper also finds that censorship Number Users of of of a topic correlates with high user engagement, suggesting that Country of Account Accounts Tweets censorship does not stifle discussion of sensitive topics. Further- Requests Specified Withheld Withheld more, the authors find that users create variants of words (known as morphs) to avoid keyword censorship [5]. Australia 3 3 0 0 Florio et al. confirmed that in 2014 the Turkish government hi- Brazil 26 33 1 39 jacked DNS traffic to censor users traffic. Users of traditional com- Canada 3 3 0 0 puters were able to circumvent censorship using TOR and VPNs. Ecuador 1 1 0 0 Unlike traditional users, mobile users used a specialized Android France 5 56 0 56 application designed to allow DNS configurations of mobile de- Germany 6 11 4 0 vices to circumvent G/4G service-provider censorship. The appli- Greece 2 2 0 0 cation was installed by 130,000 devices by August 2014. The re- India 4 18 0 3 searchers collected data that showed that some censorship activities Indonesia 2 2 0 0 began after the lift of the Twitter ban on Turkey in March of 2014. Japan 3 7 0 6 However, they did not examine the type of data being censored Korea 1 1 0 0 [10]. Netherlands 2 2 0 5 Aase et al. argued that motivation, resources, and time are three Pakistan 1 1 0 0 major elements in the application and potential uses of Internet cen- Russia 17 17 4 8 sorship. The challenge for the online censorship research commu- Spain 2 4 0 0 nity is to develop tools for measuring these three elements explic- Turkey 14 46 0 0 itly when conducting measurement studies [1]. UK 9 33 0 0 Winter et al. proposed techniques to measure and circumvent US 6 23 0 0 Internet censorship that they deployed in three countries. The tech- Venezuela 1 1 0 0 niques successfully bypassed the Great Firewall of China [35]. Total 108 264 9 117 Morrison examined the feasibility of automating the detection of censorship in microblogs without using sensitive keywords but Table 1: Aggregate Transparency Reports disclosed by Twitter using social network graphs properties and communication flow, for 18 months (Jan. 2012 - Jun. 2013) from all countries. and found his automated detection methods feasible when studying Sina Weibo [18]. In recent years, a large number of papers have focused on censor- Twitter withheld 39 tweets and one account, but the report does not ship resistance schemes (CRSs). Khattak et al. proposed an attack specify if the tweets were generated by the withheld account. model to comprehensively explore censorship capabilities and and From our data collection, it appears that a request to withhold an developed an evaluation framework to test each CRS’s flexibility account causes all tweets from that account to be withheld. In such [13]. cases, Twitter appears not to include these tweets from withheld No previous work has been attempted to quantify Twitter’s inter- accounts in the overall count of withheld tweets for a given country nal censorship mechanisms. in its transparency reporting. We verified this manually for Brazil and for Germany, but have not systematically looked at each and 3. TWITTER’S CENSORSHIP MECHANISMS every county with withheld accounts. Our initial effort was to collect as many Twitter-related reports To better understand the steps Twitter uses to implement its “Country- from the Chilling Effects database as we could find. This would en- Withheld Content" policy, it is important to examine both its Trans- able us, for example, to learn Twitter handles, hashtags, and other parency Reports and the Chilling Effects website that Twitter uses sensitive keywords around which we might later build automated to publish government withholding notices. The Chilling Effects searches. Upon initial examination, we quickly discovered how in- is an independent third party archiving service that publishes cease complete the Chilling Effects database appears to be.