"Every time you browse the web, you leave fingerprints behind"
Every time you browse the web, you leave fingerprints behind you. Websites can collect data such as your operating system, browser, screen resolution, language, language and many more that can *partially* identify you. Fingerprinting is beneficial to detect unusual activities. It can help detect botnets and even hackers. It's called fingerprinting and it's been heavily used for advertising purposes over the past years, allowing to group people with the same interests. Big companies don't care who you are or where you leave (not your home address, but location matters).
Cybersecurity aware developer.