JS doesn't have any magic to it, location information is opt-in, but your IP is a much better advertising identifier.
Things like this are seriously creepy: https://www.crazyegg.com/blog/mouse-recorder/
Canvas fingerprinting, WebGL fingerprinting, GPU, fonts etc etc etc.
Please, stop arguing, JS is a nightmare for privacy. Period
Nowadays OSes have protection for this sort of thing. But I'd imagine you could still fingerprint an OS like that. Combine that with TLS, HTTP, etc. specifics and you could narrow it down quite a bit I bet.
most people don't run their own resolvers, so at best you're fingerprinting DNS server of the ISP.
>http caches
can be easily cleared, or mitigated entirely by extensions or browser (eg. multi account containers).
[1] https://en.wikipedia.org/wiki/Transmission_Control_Protocol#...
eg: hotjar.com sessioncam.com
Legitimate tools for measuring effectiveness of pages with little in the way of nefarious tracking afaics. Also very useful for replaying user errors/problems.
That’s not how it’s tracked commonly. Similar to HTTP caches, you can fingerprint visitors by how quickly a domain request resolves for them. Sure, all of this can be mitigated. But you have to even know what to mitigate. And given the most fanatical privacy folks aren’t aware of basic timing fingerprints is a good indicator that no one is mitigating it nearly as well as they might think.