Researchers at Mozilla announced this week the launch of its "Facebook Pixel Hunt" study, which seeks to track the company's immense web-wide tracking network and investigate the intel it's collecting on users. As the name suggests, this study is focused on a piece of tracking tech known as the "Facebook pixel." Chances are, you've visited a site that uses it; these tiny pieces of tech are buried in literally millions of sites across the web, from online stores to news outlets to... well, you name it. In exchange for onboarding a free pixel on their site, these sites can then track their own visitors and microtarget ads with the same sort of precision you'd expect from a data-hungry company like Facebook.