Apparently, if you have facebook or Instagram installed on your phone, #Meta was able to track your browsing habits and link them to your real identity even if you never logged in on the web, used incognito mode or a VPN. I hope Meta gets hit with every fine in the book.

https://www.zeropartydata.es/p/localhost-tracking-explained-it-could

“Localhost tracking” explained. It could cost Meta 32 billion.

You just can't finish off Zuckerberg.

Zero Party Data
@Gargron We noticed something very odd a couple of years ago with WhatsApp web and triggered us to switch away from the app. In case others notice or can replicate it, the WhatsApp session had expired in a tab. If you were browsing in other tabs, you started seeing WhatsApp console errors as if they had taken over the whole browser and continue to try to connect.