Many places I've been won't let you buy a SIM without showing id.

Yeah. I think while not nation-state-secure, you can still improve your PII exposure to Facebook/Twitter/Google et al by buying/activating a SIM/phone-number and only using it one time for the purpose of creating an account.

I don't _think_ Twitter or Facebook are doing backroom deals with every prepaid sim vendor to be able to tie that phone number back the the identity used to register the sim card.

I wouldn't suggest you use this to register your Dream Market vendor account, but I doubt you'll end up with targeted advertising based on your other real-world web/app behaviour based just on the ID provided for a single-use burner SIM...

Yeah, what's the problem here? Presumably Facebook won't get the data on the legal owner of the number.

Germany passed an anti-terror law a few years ago, getting a phone number requires the same level of verification as opening a bank account.

Even before that prepaid phones have been a strawman argument, actually maintaining a 2nd number in the long run is quite a bit of work since it usually expires if you don't use it enough.

And then you typically need to do some kind of identity verification to activate it.

In Austria, Belgium & Germany you do, in Croatia & The Netherlands you don’t

Possible that's typical, but it's certainly not universal

Not in the UK you cant.