In March 2016, the FCC hit Verizon with a $1.35 million fine for tracking customers with a unique identifier header (UIDH), also known as a “supercookie.” It was big news when the FCC forced Verizon to allow customers to opt-out of the tracking. But what is a supercookie? Why is a supercookie worse than a regular cookie? Here’s what you need to know about supercookies—and how to remove them. What Is a Cookie? To understand supercookies, you need to understand what regular cookies are.