A recently published study conducted last year by three Mozilla employees looked at whether browsing history was enough to identify a user.
Their findings show that most users have unique internet browsing habits that allow online advertisers to create accurate user profiles.
These profiles can then be used to track and identify users in different datasets that contain even small samples of a user's browsing history.
Essentially, the study comes to dispel an online myth that browsing history, even anonymous, is not useful to online advertisers. In fact, the study shows that even a small list of 50 to 150 of the user's favorite domains can allow advertisers to create a unique user profile.
Confirmation of a similar study in 2012
The research, released this month at the USENIX security conference, is a follow-up to another academic study published in 2012.
The first study was one of the most important of the era, as the research team collected data from more than 380.000 internet users.
Between January 2009 and May 2011, the researchers asked users to access a test web site where they used some clever CSS code to determine which websites had been visited by users from a predefined list of 6.000 domains.
A 2012 study found that 97% of users who accessed this test site had a unique list of sites in their browsing history, making browser history a consistent carrier. fingerprinting.
Additionally, when users were asked to access the test site again, researchers stated that they were able to redefine users based on the browsing history profiles they had created since the first visit.
The accuracy rates were 38% when the researchers looked at 50 of the most popular domains the user visited and 70% when they analyzed data from 500 domains.
The new report
However, last year, Mozilla researchers wanted to reassess whether browsing history is still a valid "fingerprinting" player and whether the 2012 study is still valid.
The new experiment Mozilla started on July 16 and ended on August 13, 2019.
Mozilla researchers say more than 52.000 users have agreed to participate and provide anonymous browsing data.
However, this time as the data was collected by him Firefox and not through one website performing a time-consuming test CSS, the data was much more accurate and reliable. In addition, the data collected by Mozilla researchers relates to the same type of data that current Internet analytics companies collect for users - either through data partnerships, applications for mobile, internet advertisements or other mechanisms.
As before, the data collection took place in two stages, in two weeks, with users sharing their browsing history in the first week and then doing the same in the second, during which Mozilla researchers tried to see if they could to identify users.
In all, the Mozilla team said it collected data from approximately 35 million website visits in 660.000 unique domains. And this access to better quality data was immediately reflected in its findings study.
Mozilla said 99% of the browsing profiles they collected for the study were unique to each user.
This uniqueness allowed Mozilla researchers to easily redefine users in the second week of the study.
The accuracy was also higher than in the 2012 study, with Mozilla claiming to have had almost a 50% redefining rate when it checked 50 domains from a browsing history. user. This rate of redefinition increased to over 80% when Mozilla researchers expanded the data set to 150 domains.
This latest finding suggests that analytics companies and advertisers do not need huge lists of browsing history data to track users, and that each user's browsing idioms and website favorites identify him / her.