PopSci: “Picture a high school student who wants to go to college, likes to cheer on her school’s football team, and plays in a sport or two herself. .  One day after school, she signs up for an official ACT account so she can schedule her college entrance exam and see what score she gets after taking it. Then, she researches a few colleges through the Common App’s website, and like more than a million students every year, she uses the site to start an application for her dream college.  She spends a few minutes starting a presentation for class using the website Prezi. On a homework break, she registers for her high school’s after-school sports program through a service called ArbiterSports, then she hops on her phone, remembering to order a yearbook through the company Jostens. Long day over, she takes out her laptop and flips on her school’s big football game through the NFHS Network, a subscription service for high school sports. Here’s what the student doesn’t know: Although she surfed the internet in the privacy of her home, Facebook saw much of what she did. Every single site she visited used the Meta Pixel, a tracking tool that silently collects and transmits information to Facebook as users browse the web, according to testing by The Markup. Millions of invisible pixels are embedded on websites across the internet, allowing businesses and organizations to target their customers on Facebook with ads…”