[IAmEveryone]

It's never illegal for the user to create an account. It can be for the company.

As a heuristic: a website such as HN that is available in the EU but doesn't specifically target EU "customers", and that isn't itself or via some subsidiary registered within in the EU is perfectly fine.

I believe the same is also true if you allow EU customers to buy in your online store as long as it's implemented as just a "country" form field and, again, you are not registered in the EU/have no distribution warehouse there, and so on.

I've seen the New York Times being cited as a sort of goalpost of what's still ok: even though they have journalists in Europe, they have no sales presence, and are clearly aimed at the US market.

No idea about Amazon, though.