In Norway, taxable income is public information. It used to be that it was so public that newspapers would put up searchable databases where you could enter name and postcode to get a list of everyones income and fortune. It's been restricted a little bit. The idea is that it acts as a deterrent to tax evasion and money laundering (your neighbour gets suspicious about that new Ferrari you bought) etc..
I don't really have much of an opinion about whether it's good or bad - people mostly don't care other than 5 minutes of excitement when the numbers were out when online news sites still published them.