The most interesting is that hiding salary information does not work. If you don't receive a raise similar to the average of your firm, sooner or later you will

The most interesting is that hiding salary information does not work. If you don't receive a raise similar to the average of your firm, sooner or later you will find out and search for another job that will pay average or better salary. And if you receive above average, then you will either be promoted to a level where you're average again, or have your future raises decreased. Basically, the only thing that works is a promotion, which is clearly a public event. So, it would be much better if everyone had their salaries made public, with salaries clearly tied to promotion levels.