Impact of New Zealand Copyright Legislation on BitTorrent Population

Apr 10, 2012: Number of BitTorrent users in New Zealand declines after copyright legislation is put into effect.

Led by Zachary Bischof

On September 1, 2011, the New Zealand government put into effect the Copyright Infringing File Sharing Act, a three strike policy with penalities up to $15,000 and disconnection of service for illegally sharing copyrighted material online.

The plot below shows the number of unique BitTorrent users seen in New Zealand according to data reported by Ono users. In the days leading up to the enforcement of the bill, the maximum number of BitTorrent users seen throughout a day from New Zealand consistently peaks at approximately 1300 users seen in an hour. However, after September 1st, the daily maximum number of peers seen per hour does not surpass 1000, usually hovering around 750 peers. Furthermore, once the law is put into place, the number of peers seen per hour begins to dip below 500 during off-peak hours.

Time (UTC)
# of Peers seen
Number of peers seen online in New Zealand before and after the new copyright legistation is put into effect. The shaded region begins on September 1, 2011 at midnight UTC.

Internet Outages in Palestine

Nov 16, 2011: Cyber attacks affect BitTorrent usage in Palestine.

Several news sources (CNN, BBC) have reported that on November 1st, Palestine's networks were the target or cyber attacks. Here we examine how BitTorrent users were affected by these attacks and subsequent network outages. The graph below shows the number of BitTorrent users seen online per hour. We see a sharp drop of about 75% in the number of connected users in Palestine for a few hours, occurring between 1 am and 4 am (UTC) on November 1st. The drop begins around the same time the renesys blog reports a drop in reachable networks in Palestine.

Time (UTC)
# of Peers seen
Number of peers seen in Palestine between October 29th and November 3rd. The shaded region represents the day of the cyber attack. The dip in users on November 1st occurs at approximately the same time as what was reported on the renesys blog.

Regional Impact of Earthquake and Tsunami in Japan

Nov 7, 2011: Effects of the disaster on BitTorrent population correlates with earthquake and tsunami intensity.

As a follow-up to our previous article on the Tohoku earthquake and tsunami, we investigated the regional impact of the disaster on the BitTorrent population. We analyzed BitTorrent usage, along with reported earthquake and tsunami data for each prefecture to see if there was a correlation between the data sets.

We began by checking which regions saw the largest drops in users and as well as the regions that were most affected by the disaster. The graphs below show for each prefecture, the change in the BitTorrent population after the disaster (left), the intensity of the earthquake (center), and the height of the tsunami (right). To understand the impact on the BitTorrent population, we compare the number of users seen 24 hours before and after the disaster. In the BitTorrent population graph, a prefecture colored red means that the prefecture saw a drop in BitTorrent users and green means there was an increase. The brighter the color, the greater decrease or increase in BitTorrent users. In the earthquake and tsunami intensity graphs, the brighter the red means a stronger earthquake and a higher tsunami, respectively. The maps show that the BitTorrent population in prefectures closest to the epicenter (marked by the "X" on the maps) saw a greater decrease in BitTorrent users.

We quantified the relationship between BitTorrent and the disaster by performing correlation analysis. Here we found a a significant negative correlation between the drop in population and the height of the tsunami (r = -0.62), meaning the higher the tsunami, the larger the drop in the number of peers in that prefecture. We found an even stronger negative correlation between the logarithm earthquake intensity and BitTorrent impact (r = -0.81). This means that regions with higher earthquake intensity, tended to see greater drops in BitTorrent usage.


Change in BitTorrent population

Earthquake intensity

Tsunami intensity