You say that, but in 2014 they introduced protections that made it impossible to search the database anonymously. People are now informed who has accessed their information, when, and are provided information about the searcher in question, such as birth year and postal codes. Also, a person is only allowed to see a limited number of people's returns.

skatteentaten.no also lists a bunch of other privacy restrictions that they have in place.

This was, in part, to discourage criminals using the database to target wealthy people, and to curtail some of the harassment that resulted from this information being brought to light. This change apparently was a enough to dissuade the majority of usage, as most people now apparently just search for themselves.