> How helpful could zoom level possibly be towards fingerprinting a user It's just another bit of information. Collect enough bits and eventually you'll have

> How helpful could zoom level possibly be towards fingerprinting a user It's just another bit of information. Collect enough bits and eventually you'll have a likely-unique id. It doesn't matter what that information is as long as it somehow is about you (and not e.g. random). If you want to fingerprint, you just try to grab every bit of information you can, no matter how irrelevant it is taken on its own. It doesn't need to say anything about a cohort to be useful, it just needs to enable identifying so that they can track you around and eventually combine other information they discover about you in a profile. And it doesn't even need to be 100% accurate; "that person coming from a Telia-owned IP visiting this site again at 2 AM GMT+2 using Firefox Nightly on Linux, with 1440p display and 120% zoom level and no fonts installed" could be two or three guys if I'm lucky but it's probably close enough to not matter for someone who just wants to sell me garbage. If your zoom level were the only thing, then indeed it would be useless. Problem is, browsers leak lots of bits. It's better to try plug all leaks you can than it is to ask whether that particular leak alone is harmful enough.