We describe a few highlights from our recent paper on studying peoples’ use of browser-based blocking extensions that will be presented at the 2018 Usenix Symposium on Usable Privacy and Security (SOUPS).
What did we do?: One of the ways in which people can block online tracking on the Internet is using browser-based blocking extensions such as Ad blockers, Content blockers and Tracker blockers. In our study, we asked why people use these extensions, what their knowledge of online tracking is, and what users do when these extensions fail to function correctly.
How did we do it?: We conducted two surveys using Amazon Mechanical Turk and measured what extensions survey-takers were using, if any. In the first survey, participants reported details about the extensions they used and how they thought online tracking worked. We then asked them why they used the extensions they reported, how they learned about them, and how long they had been using these blocking extensions. We also conducted measurements to check whether participants were using the extensions they mentioned. In the second survey, which we administered only to the subset of participants who reported using these extensions, we asked participants about their experiences when their extensions “break” websites they are trying to access.
What did we find?: We have three main findings. First, our results show that blocking extension usage only weakly relates with an advanced understanding of online tracking in the real world. Second, we find that each extension type has a primary reason behind adoption that is in line with expectations: users adopt Ad blockers and Content blockers primarily for user experience gains and rarely take full advantage of the privacy benefits of these blockers, other users adopt Tracker blockers for privacy reasons. Finally, our results show that current users report that they rarely experience website breakages because of their blocking extensions. However, when users are poised with a choice to disable their extensions to access the content they are trying to reach, they base their decisions on how much they trust the website and how much they value the content they desire to access.
What are the implications of the work?: Based on our findings, we make two suggestions. First, given that both blocking extension users and non-users do not fully understand the landscape of online tracking, we suggest that system designers should focus their efforts on building systems that automatically enforce tracking protection as opposed to having users take action to protect themselves (such as by installing an extension). We argue that browser vendors can play an important role in facilitating this type of default privacy protection. Second, we suggest that blocking extensions can be further improved by better understanding how website developers embed third-party trackers and deliver content through their websites so that non-use (disabling) is not forced upon users.