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...