Almost as interesting, you can (as I understand it) look up the current salary of anyone you want to. Though in doing so they will be notified that you have done so.
So you can still lookup how much your co-workers earn without them knowing you asked for. But generally people are open with how much they earn, so it's really not an issue.
Hint: it might end up leading to an uptick in antisemitism.
However there is a lowtech way around this. Taxed income is published yearly in a book that resembles an old phonebook, Taxeringskalendern ("the tax calendar"). Freedoom of the press, see?
This book (or the part of the book that covers your region) will be available at your local library in the "reference" section. For most people you take the number from the book and divide by 12 and you have a lower bound of their monthly salary. Unless they are stalking you at the library noone will know. Very useful when going into salary negotiotiations to know aprox what the rest of the team and your boss makes.
There are companies that download the entire salary database and sell 'lookups' in their database. This way you can look up anyone you want and no one gets notified of anything.
No. Depends on how you look it up, but you could just send an email (from anonymous account if wanted) to the tax agency asking for someones salary. You get an answer back in a few days without them being notified.