Not Swedish, but the relevant one in the parent comment is probably mandatory residency registrations, and I'm surprised the data is so publicly accessible there. There are usually attempts at creating firewalls in many countries so the data that one agency collects isn't directly linked to that of other agencies, preventing broad files on individuals.
It's similar in the sense that it's a unique number assigned to each person, but the fact that it's publicly available means that it cannot be used as authentication.
We have a similar issue with Finnish Personal Identity Codes, which are legally public, but there are restrictions related to their processing. Which leads to the common misunderstanding that they're secret, so they're used for authentication. It's a mess.
Now, with increasing criminality due to mass immigration there is only a question of time until these services becomes illegal I think.
I have personally been subjected to a stalker, so it will be nice when these services disappear for me personally but I honestly think the utility of them are great. If you find a wallet for example, you can easily find this person and call them due to these services. But for now, the only way to be truly anonymous in Sweden is to get a protected identity which is pretty much impossible to get or to buy some land and switch your home address to that place. People can still get all the properties you own with your "Personnummer" (social security number) but it is harder, less known, takes more time etc.
I'm not well read on the issue but a lot of things are digitalized in Sweden. It's a cashless society, where everyone have a personal number that they can use for government service & signing up for phone contracts. The tax institute (like USA:s IRS) sends their deductions out digitally, and AFAIK they have a very open API a lot of digital services in Sweden use for online identification of a private person. So I assume those pages probably use the tax-institutes API for personal information, and then other APIs (such as real-estate portals) to tie information together.
Norway has had similar tax return approval by text messaging for almost 20 years.
The government doesn't know about every purchase you make but there is a lot of data sharing. However there is a lot more consumer protection and less power lies with unaccountable corporations than in many other capitalist countries, where corporations have almost free reign and have powerful influence over society, economy & politic. For example, credit scoring is relatively new here and is a lot less intense than other countries. In places like the UK/USA, credit scoring companies control your financial possibilities. Much less so in Scandinavia.
There is a small number of people for whom a cashless society poses problems, but it's probably less, and a different subset, than you think. Those I know of through association tend to be those who suffer severe mental health issues. Old people have bank accounts, debit cards and mobile phones for digital transactions. As for homeless people, there are less of them in Scandinavia than in other countries. Almost all of them will still have a bank account and a mobile phone and be receiving state funds digitally. (Homelessness is not defined as living on the street, almost all the homeless are in temporary housing.)
All this is marketed as better for crime prevention, less bank/store robbery. Ofcourse this only pushes the cost on the individual in the end though. If you can't rob the store, you can still find valuables in private houses with much lower security. Or just stop any youth on the street. Chances are they have an expensive phone if nothing else.
I think the crime thing might not be a direct link, as a bank robber and an opportunistic street thief are probably different people. There is less opportunistic crime than elsewhere as a big driver of crime is people's situation which, in general, aren't bad enough to resort to crime. I'm still unnerved by the lax security everywhere, e.g. the tiny bolts and padlocks in common storage areas in apartment blocks, which are an increasing target for thieves as they are easy pickings.
Another benefit is BankID, which makes fraud & identity theft is a lot more difficult as there is an easy and secure way of identifying yourself online. Even with somebody's ID number you can't impersonate them in most situations. This is something I've really appreciated working in the finance industry. The old way of calling up and accepting people's identity purely on trust never sat well with my non-Scandinavian mind.
Sweden has a different attitude to this kind of information that is fundamentally more about transparency than privacy, so it's not perceived as an issue.
And there are even more extreme versions, like ratsit.se
where you can pay to get credit information on anyone.
Personally I think that what ratsit does is probably too far, and maybe it shouldn't be legal.
But in general I like our "public information" system, that lots of government information is available to every citizen, I find the benefits of being able to check what the government and those with power does (journalism would be way harder without this), outweights the negatives.
There are apps for Eniro and Hitta that could tell you if an incoming call is from a known callcenter for example. Not sure they still work after google tightened up security.
I'm always amazed I can't find someones phone number outside Sweden when I need one. Here it's just a few clicks away. Sure you can ask to be removed from their register but most wants to be there.
Another privacy nightmare with complete vehicle history -- better than carvertical.com or vin-info.com
It's kind of hilarious.
On the page you can search peoples home address, phone number, date of birth, other members living in the same house, real estate value, mortgage rate, all by searching their names. I successfully once identified a parent of a owner of a lost wallet, only containing a gym card with last name on it. Found her phone number on the site, called her and gave her the wallet.