Fault Tolerance comes to Twitter in the form of Twimight

Making twitter fault tolerance may not seem like a priority at first thought, I mean surely in the unlikely event of the network failure, those 17 year of girls can will just have to learn to wait before they can tweet about there new jimmy shoes.

But if you consider further the situations in which network failure is likely to occur such as natural disaster, this is when twitter is needed the most. Here is an xkcd to illustrate the point

Seismic WavesIts difficult, particularly if you didn’t grow up with twitter to understand why keeping social network alive in the event of a disaster is so important. But like it or not, twitter is just as essential in some peoples live than other (more traditional) communications form such as text messaging or TV broadcasts. In fact, it could be argued that since scarcity of information is often a problem for individuals in a disaster, the broadcast properties of twitter, make it potential more useful than  uni cast text messaging or voice calls.


The application to which has introduced this ‘disaster mode’ to twitter is called Twimight, its a open source twitter application with a couple of very interesting features. I’ve going to test out the application on my nexus 7.

The basic interface of the application is very similar to that of the standard twitter application but an exploration of the overflow icon highlights a range of features, that could be particularly useful in a disaster.

The basic idea of how this application aims to enable connectivity in a disaster situation is as follows:

  • Android device users install the application and get there friends to do the same
  • Bluetooth is used to pair your android device with your friends android devices
  • Disaster occurs so network connection is lost and the user enables the ‘Disaster Mode’ within the application which turns on bluetooth in an always discoverable mode
  • The user tweets despite the lack of a network connection
  • The tweet is send (via bluetooth) to friends within range
  • The disaster is over and the network connection is restored
  • Tweets are automatically posted to the web


Twimight also support a plug-in called android-sensor-twitteth


The twitter disaster server is used to collect user activity and environment data


In case of a disaster, individuals do not want let any other peice of hardware to carry around but given that 3/4 of the world’s population now have access to a mobile phone and that twitter now has 500 million users, mobile twitter access has the potential to be a powerful force for good.

The UX is designed such that its simple to use in a stressful situation, with the user enabling the ‘disaster mode’ in the application with a simple check box (though this box is a little harder to find than I would ideally like)


Before Bluetooth can be used for the automatic spreading of tweeter messages, the devices must be paired, those potential irritating to the user, this is essential to allow the application to make up of the bluetooth protocol.

Once the user has enabled ‘Disaster Mode’ the application enables bluetooth, scanning takes place every  2 mins +- 20 sec


Power consumption is important considation for all mobile applications, in this case it is particularly important as its more unlikely that users will have access to pwer supplies and suitable chargers. In ‘disaster mode’ the use of bluetooth much therefore be considered carefully. Bluetooth scanning time need be as high as possible to increase the speed of the transition of tweet, whilst using minimal battery life. The power saving heretics for Twimight are set so that the scanning interval is  reduced when battery is less than 50 % and scanning is stopped when battery is less than 30 %.


This application like many others, we be almost unless to individuals unless the number of devices that the application is install on reaches a critical number such that in the case of a disaster, there is at least one individuals within bluetooth transmitting distance with the application installed

This application will not be able to reach this critical mass, because individuals will not have the foresight to install such an application, “just in case” they were to need the disaster mode it provides.

Consider instead, the hypothetical case that twitter was to adopt such a “disaster mode” into its own supported mobile application.

The official twitter application has 578,194 downloads from the play store and 500 million activated android devices. So twitter and android are powerful platforms but with a typical bluetooth range of 10 m and the requirement for pair devices, is bluetooth really the best wireless protocol for this use


Tsukuba is a city of 200,000 located in Ibaraki Prefecture, Japan. Tsukuda lost electricity, communication networks and water immediately after the Great East Japan Earthquake of March 2011. The lack of power meant that smart phones became key devices for communication. Muneo Kaigo has written an excellent Keio Communication Review, examining the use of twitter in Tsukuda in the 7 days following the earthquake and I thoroughly recommend it


twimight hosting on google code –  code.google.com/p/twimight/
twimight unofficial application location –  twimight.googlecode.com/files/twimight_0.9.2.apk
android-sernsor-twitteth hosting on google code – code.google.com/p/android-sensor-twitteth/
the paper – people.ee.ethz.ch/~hossmath/papers/extremecom11_twimight.pdf
presentation from Extremecom 2011 – www.slideshare.net/thossmann/twitter-in-disaster-mode-extremecom-2011 
Keio Communication Review No. 34, 2012 – Social Media Usage During Disasters
and Social Capital: Twitter and the Great East Japan Earthquake –

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