There's a company, currently called Tie (meettie.com), formerly known as Revenue Roll, who promises to "de-anonymize your highest value web traffic", which in practice means that they give you an email address for retargeting, for a user who visited your site without ever explicitly providing any identifying info.

The old site had a blog post [0] where they explicitly said they were using fingerprinting, and even called it "privacy-compliant".

I'm sure they're not unique in the service they provide, but that was the first time I'd seen someone brag about browser fingerprinting.

[0] https://web.archive.org/web/20240527125312/https://www.reven...

I notice they have an Opt-Out form here: https://app.termly.io/dsar/ee5088c4-5eb2-475c-a9ea-9376f1b70...

It's pretty hilarious legalese and tells you nothing about what it even achieves. Maybe makes you a Very Important Marketing Target.

One thing that struck me was the 'Under penalty of perjury, I declare all the above information to be true and accurate'. Shame they seem to require validating request by email. It'd be fun to take a PII breach and throw all the emails you find at 'em.

Why aren't privacy orgs trying these services.