a) Techniques like this can identify a unique user to 99.5% accuracy e.g. https://fingerprint.com https://fingerprint.com b) It can identify the user personall

a) Techniques like this can identify a unique user to 99.5% accuracy e.g. https://fingerprint.com https://fingerprint.com b) It can identify the user personally because many web sites use pixels where we link the fingerprinted user to an email address and then send both to Meta, Google, Reddit etc. And since browsers like Chrome allow long lived first party cookies this works because users remain signed in for over a year.