Adblockers might not be enough.

Some services claim to turn "anonymous" visitors into actual email addresses (and some other basic info), likely via identity graphs (IP/device/hashed IDs).

I've heard of cases where people are getting outreached (via email) after just visiting a product website, even with an ad blocker on, using a private browser (Brave or similar).

Opensend is one example. They're pretty open about it in their FAQ [1].

[1] https://www.opensend.com/faq

Proper adblockers like uBlock Origin block privacy invasive trackers that do this too.