In Europe, police usually have a right to request information from companies and people. This is codifed into law, there's not necessarily any legal procedure for how it needs to happen.
There are some standards on how inter-country information is requested.
Agreed, except that Ireland en England are part of Europe.
Also (and I'm not sure on this part) in The Netherlands we have WvSr aka Sr (Wetboek van Stafrecht, criminal law) and there's privaatrecht (aka burgerlijk recht, civiel recht). Subpoenas would be vordering(srecht). Government issue these as well, but it seems to fall under civil law.
Yes, there is a civil/criminal divide, this is not so much related to being civil/common law
(and just because this is HN, see the graph at the bottom of the page for a French example - though they call it civil and penal jurisdiction https://cours.unjf.fr/repository/coursefilearea/file.php/105... )
There absolutely is in many European countries. The divide is just along different lines than in US.
https://www-librededroit-fr.translate.goog/quelle-est-la-dif...
The Twitter user is pseudonymous at best, and was posting objectively true data, publicly available, regarding a notable, public person in these United States.
The FB user in TFA was anonymized by group membership, and posting allegedly defamatory and untrue information about a private person.
A better comparison would be the Twitter user that was tweeting Elon Musk's jet flights. This was before twitter was purchased, and Elon Musk was not able to get the court to order Twitter to hand over that information.