Recently, I read an article about device fingerprinting, which argues that we’re in the post-tracking-cookie era. They’re no longer needed, because every browser can be fingerprinted with 100% accuracy.

https://royfish.dev/fingerprints-are-the-new-cookies

There’s an EFF page which allows you to test your device fingerprinting. https://coveryourtracks.eff.org/

The information theory idea is that while there are millions of people who have the same time zone, time zone offset, fonts, etc., it’s the combination of all these things that makes it possible to identify.

The EFF has a page on this, which explains. After establishing that 33 bits of entropy is needed for identification:

So for instance, if we know someone’s birthday, and we know their ZIP code is 40203, we have 8.51 + 23.81 = 32.32 bits; that’s almost, but perhaps not quite, enough to know who they are: there might be a couple of people who share those characteristics. Add in their gender, that’s 33.32 bits, and we can probably say exactly who the person is.