Mozilla Launches Facebook Pixel Hunt to Reveal How You’re Tracked Online

Mozilla researchers announced the commencement of their “Facebook Pixel Hunt” investigation this week, which aims to follow the company’s massive web-wide tracking network and scrutinize the data it collects on users. This study, as the name implies, focuses on a piece of tracking technology known as the “Facebook pixel.”

You’ve probably visited a site that employs it; these tiny pieces of technology are buried in literally millions of sites throughout the web, from online businesses to news outlets to… well, you get the idea. These sites may track their own visitors and microtarget advertising with the same precision you’d expect from a data-hungry firm like Facebook in exchange for installing a free pixel on their site.

In exchange for granting these sites the ability to track every pageview, purchase, search query, and much, much more, Facebook (naturally) expects this data to be shared with it as well. When a website visitor has an account on a Facebook platform, this offsite data is simply merged with whatever Facebook already knows about that individual. If they don’t have a Facebook account, the corporation nevertheless collects that information and uses it to develop a “shadow profile” of that individual. These are the kinds of shady tactics that Mozilla’s team want to investigate with this project, and you can help them if you use Firefox.

Mozilla collaborated with Markup reporters to gather information about Facebook tracking by using Mozilla Rally, a free browser extension that collects data sent out by Facebook’s pixels as you browse the web. Aside from that information, the extension also records the amount of time spent on various web pages, the URLs that the browser visits, and other information. In its introduction, Mozilla was eager to point out that the only data exported by the extension will be de-identified and not shared with any third parties other than the Markup’s reporters.