No shame in that! It is actually pretty well-written, and it has some engaging points. I'm not "anti-rationalism" or anti-this-guy or anything like that. LessWrong did more for global altruism than I ever will.
I'm just pointing out that a person who has dedicated their entire public persona to an ideology (or lack of one) is probably not joking when they start evaluating romantic partners with supposedly objective percentages.
Totally! Browser and device fingerprinting are commonly used as first-line defenses against ATOs (account takeovers). There are other kinds of fingerprinting, like those that can learn about your installed hardware and drivers. Really, I'm learning about more fingerprinting methods all the time. That said, decisions are usually made based on several different information sources. These include variables like:
There's even some buzz around "behavioral biometrics" to identify individuals by how they type, but this is still not the sole method of identification. It's mainly about flagging bots who don't type like humans. However, learning how an individual types can help you determine if a subsequent visitor is the actual account owner or a bad actor.
In my experience, fingerprinting and adjacent identity proofs are rarely used in isolation. They're often employed for step-up authentication. That means if something doesn't match up, you get hit with a 2FA/MFA prompt.
Step-up can be pretty complex if you want it to be, though, with tons of cogs and gears in the background making real-time adjustments. Like you might not even realize you've been restricted during a session when you log in to your bank account, but once you try to make a transfer, you'll get an MFA prompt. That's the UX people in action, trying to minimize friction while maintaining security.