1.
WARNING
CONTENT IN THIS TALK IS
OFFENSIVE
AND UNCENSORED
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2.
Measuring 4chan’s Politically Incorrect
Forum and Its Effects on the Web
Gabriel Emile Hine, Jeremiah Onaolapo, Emiliano De Cristofaro,
Nicolas Kourtellis, Ilias Leontiadis, Riginos Samaras,
Gianluca Stringhini, Jeremy Blackburn (@jhblackb)

3.
4chan
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4.
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5.
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6.
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7.
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8.
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9.
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10.
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11.
Why Do We Care About 4chan?
• It’s a niche site, right?!
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12.
What Exactly Is 4chan?
• An image board
• Conversations grouped
into threads
• Anonymous
• No user accounts
• Ephemeral
• Dangerous?
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13.
Basics
• An “original poster” (OP) creates a new thread by
making a post
• Single image attached
• Other users can reply
• With or without images, and possibly add references to
previous posts, quote text, etc.
• NB: Quotations are implied by the > symbol, as users regularly
use it to put words in other posters’ mouths
• No likes, share, favorites, etc.
• No validation from other users except more posts!
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14.
Boards
• 4chan separates conversation into different areas
of interests known as “boards”
• We focus on /pol/ (politically incorrect)
• Also look at /sp/ (sport) and and /int/ (international) for
comparison
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15.
/pol/ - Politically Incorrect
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16.
/pol/ - Politically Incorrect
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Extremely lax moderation
Volunteer “janitors” as well as ”admins”
Almost anything goes

17.
The Bump System
• Limit each board to N live threads
• Threads ordered by MRU
• A new post in a thread “bumps” it up to the top
• Create a new thread  An old thread dies
• Bump limit
• Max of times thread can be bumped
• Ensures that no discussion will dominate forever
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0.00
0.25
0.50
0.75
1.00
1 10 100 1000
Number of posts per thread
CDF
10−5
10−4
10−3
10−2
10−1
10
0
0 250 500 750 1000
Number of posts per thread
CCDF
board
/int/
/pol/
/sp/

18.
The Bump System
• Limit each board to N live threads
• Threads ordered by MRU
• A new post in a thread “bumps” it up to the top
• Create a new thread  An old thread dies
• Bump limit
• Max of times thread can be bumped
• Ensures that no discussion will dominate forever
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0.00
0.25
0.50
0.75
1.00
1 10 100 1000
Number of posts per thread
CDF
10−5
10−4
10−3
10−2
10−1
10
0
0 250 500 750 1000
Number of posts per thread
CCDF
board
/int/
/pol/
/sp/
Just crawling data is challenging!
We need to build a crawler that
works with the ephemeral
nature of 4chan

19.
Datasets
• Crawled /pol/, /sp/, /int/
• June 30 to September 12
• Using 4chan JSON API
• Methodology:
• Every 5 minutes take a snapshot of catalog
• Once a thread is pruned, retrieve full/final
contents from archive
• NB: Archives are pruned after 7 days!
• EMAIL US IF YOU WANT TO WORK ON THIS
DATA WITH US!!!
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/pol/ /sp/ /int/ Total
Threads 217K 14.4K 24.9K 256K
Posts 8.3M 1.2M 1.4M 10.9M

20.
or ?
Hate Speech Usage
• Crowdsourced dictionary
• Manually filtered a bit
• /pol/ by far most
hate speech use
• /pol/ 12%
• /sp/ 7.3%
• /int/ 6.3%
• Twitter 2.2%
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21.
Raids
• Attempts to disrupt another site
• Not a DDoS
• Disrupts community that calls service home, not
the service itself
• Raids are a favorite past time on 4chan
• “Pool’s closed!”
• Have become less “funny” and more “scary” lately
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22.
Extended
version
only Case Study: Operation Google
• /pol/ got wind that Google
had some anti-hate AI
• /pol/ does not take kindly
to censorship
• Unless they are censoring
things of course ;)
• /pol/ has beaten AI before
• Search for “MS Tay bot”
• google = nigger
• skype = kike (jew)
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23.
Extended
version
only
Impact of Operation Google on /pol/
• Huge spike in
code word use
• No dip in “real”
words
• Relatively short
lived…
• Why?!
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24.
Extended
version
only
Not That Successful on Twitter
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25.
Raids On YouTube Videos
• Many YouTube links posted on /pol/
• We’ve anecdotally observed them raided
• Can we find quantitative evidence of raids?!
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26.
How Might Raids Happen?
• Someone posts a YouTube link
• Maybe with a prompt like “you know what to do”
• Thread is an aggregation point for raiders
• E.g., “Hah! I called that person a nigger!”
• If raid is taking place:
• Peak in YouTube comments while thread alive?
• /pol/ thread and YT comments synchronized?
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27.
What’s a YouTube Raid Look Like?
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28.
Activity Peaks
• YT videos with peaks during 4chan thread
• Determined via PDF of commenting timeseries
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29.
Activity Peaks
• YT videos with peaks during 4chan thread
• Determined via PDF of commenting timeseries
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14% of videos see peak
commenting activity during
/pol/ thread lifetime

30.
Synchronization Example
• Two series
• Second randomly shifted from first by 0.2 on avg
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31.
Synchronization Example
Blue lines 
per-sample lag
Red area 
density of the lags
Peak of density curve = 0.2
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32.
How Can We Validate?
• Just because there is synchronization, doesn’t
mean a raid is going on
• In fact, we expect some background noise
• We need to come up with metric to validate
• If a raid is happening, we would expect to see
elevated levels of hate speech
•  more hate comments per second
• Raiders likely using same YouTube accounts?
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33.
Evidence for Raids
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34.
Evidence for Raids
• Synchronization  More overlap
• I.e., the same YouTube commenters
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35.
Summary
• Bump system leads to interesting dynamics
• Forces fresh content
• /pol/ is a hateful place
• Compared to Twitter and even by 4chan standards
• There is evidence for raids
• High level of synchronization between 4chan/YouTube
• High overlap of YouTube commenters
• Lots of results I didn’t show
• 4chan users are well distributed throughout the world
• Staggering amount of original content posted
• Check the paper/our extended technical report!
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36.
Thanks for your time! Questions?
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37.
Backups
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38.
Geographic Distribution of Users
• /pol/ shows the flag of the country the user is posting from
• Normalize number of threads created per country by that
country’s Internet using population
• /pol/ users really well distributed!
• Native English speaking countries most highly represented
• Plenty of other countries really well represented too though!
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39.
Are Flags Trustworthy?
• Use spectral clustering of the topics that each
country posts about
• The clusters follow real world socio-political blocks
• While flags are not perfect, they seem reasonable
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40.
Image Usage
• 1,003,785 unique images out of 3,216,972 total images
• 800 GB worth of images in ~3 months
• 70% posted once
• 95% no more than 5 times
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41.
Most Popular Images on /pol/
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