In Scandinavian countries I think you can look up someone's income tax - but it's a little bit bureaucratic and that person will also be notified that you looked them up. Not sure if it's necessary, but the sharing logic is necessary.
If you want to know how someone voted, you have to pay $5 for each person, they will be notified, and you can't publish the information, or something like that.
Or better yet - it should be confidential.