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Development by Hang Do Thi Duc, Becca Ricks and Joana Varon
Special Thanks to Brett Gaylor and Kevin Zawacki

Introducing an open-source browser extension that helps you thwart targeted advertising on Facebook


Even if you don’t care about being chased by the latest sneaker or flight destination that you’ve recently searched for, the ongoing Facebook-Cambridge Analytica scandal has shed light on a common and disturbing practice undertaken by the world’s largest social network: the vast amount of personal data gathered about us is progressively used to shape our behavior, wishes and needs.

For many — especially women and non-binary people — this approach can be even more aggressive, reinforcing gender roles, heteronormativity and, therefore, discrimination against diversity.

Facebook uses our browsing data to infer our class, gender identity, sexuality and many other aspects of our lives. It infers whether we are up for a date or about to get pregnant (and can probably even guess with whom), if we are sad or in the mood for a party (or both). Furthermore, the increasing variety of apps that track our bodies and sexual habits - such as dating apps and period trackers — not only profit from our most intimate information, but also, very likely, even if they are not developed by Facebook, their services and databases are at least connected to Facebook through partnerships for “easy” login.

These are all valuable information to advertisers. As we have shown in our investigation about Gendered Targeted Ads it enables them to show you ads for cribs, baby monitors, weight loss programs. Or, if you are of a certain age, it lets them invade your timelines with fertility program ads or suggestions to freeze your eggs. Some find it quite annoying to see that Facebook is allowing advertisers to have sensitive data about you to suggest how you should be or what you should care about.

Facebook says that people can control how advertisers target them by using Facebook’s Ad Preferences page — but how effective is that? We’re uncertain whether the new ads transparency plans and privacy controls that Facebook has introduced will actually better protect our information.

That’s why we built — a browser extension for Firefox and Chrome that helps people to thwart future targeted ads and gain transparency into Facebook’s ad platform.

How does it work?

First, you need to quickly add it to your browser:

To install it on Firefox, click here

To install it on Chrome, click here.

In case you use an adblock, please, disable it, our goal is not to block, but to see how they are targeting us. The extension also do not run if you are in a private window.

Once these steps are done, starts to assemble a running list of the Facebook ads you have been exposed to. You can now see the bigger picture: how Facebook sells you to advertisers, and how Facebook has categorized you. Is that you? Do you want to be seen as that person?

Besides giving you transparency, the tool also helps you minimize data about you. While Facebook constantly assigns you ads categories and the possibility to edit them, most people don't even know it or have the time to clean out all their ad preferences one-by-one every day. makes it easier. By clicking the “Clean Ads” button on the dashboard, you automatically remove all those categories that are visible to advertisers, while also getting more insight into how you are being targeted.

Over time, you can see whether the types of ads you are seeing have changed over time, according to how often you run the cleaning function of the extension. You can gain more insight not only into how advertisers are targeting you, but also whether or not the privacy controls Facebook has implemented are effective at preventing ad targeting.

Here’s a short video of in action cleaning your ads categories:


About the creators

Hang Do Thi Duc is a developer, engineer, and Mozilla Fellow. She is the creator of Data Selfie, an open-source browser extension that provides a personal perspective on data mining, predictive analytics and your online identity. @hangdothiduc

Becca Ricks is a technologist, researcher, and Mozilla Fellow based at Human Rights Watch. Her work investigates how social platforms collect, monetize, and disclose data about people online, and the biopolitics of social algorithms. @baricks

Joana Varon is a Brazilian researcher, founder and executive directress of Coding Rights and a Mozilla Fellow. She is the creator of Chupadados, an art-and-journalism project that explores women’s online privacy in Latin America. @joana_varon

For more information and a FAQ about, visit the tool at Github.