[411mrc]

It's well known, not the poster's personal claim:

https://boingboing.net/2017/11/08/involuntary-profiling.html

FB goes so far as to buy your data from others, which is why I block all trackers. I'm sure I still leak data to FB, even though I never joined, and never will.

[rconti]

Interesting! Thanks for the informative reply. This feels like the kind of thing I probably read about at some point but subsequently forgot.