It can get much creepier. It's possible to reverse image search a person's profile picture from one site to find out where else they have profiles - given that they reuse their profile picture - which many do.

I’ve been wondering when we’ll see a service that lets you upload a headshot from the company directory or Facebook, and returns every nude of that person that ever found its way onto the internet.

there is such a service already, sort of. it's called pimeyes.com

Interesting. I haven’t tried it, but there’s a really specific set of sites it would need to crawl in order to achieve maximum chaos.

Wait until you find out how HackerNews harvests your data, uses services that use data lakes of bulk collection to confirm your identity, and sell what you generate without your permission.

I'm still waiting to find out about that. Maybe you'd be kind enough to elaborate.

Why is it creepy?

If you don’t know at this point, I can’t explain it to you.

Some people find stalking, and tools which could enable stalking to be undesireable.