I never understood the kind of culture where salaries are secret. How good is that? In academia you know exactly how much everybody earns (it's determined by your tenure status) and nobody makes a fuss about it.
It's only a taboo to the extent that other people are vaguely worried that it might be. :-)
It only helps employees to keep salaries opaque.
On the other hand, nothing good ever comes out of sharing salaries with current coworkers. If you make more they are going to be upset.
You don't ever want your pay tied to seniority. You want it based on the value you can deliver. That way, you with your 10 years of experience and proven ability to ship good products get to make twice as much as Senior Dev John with 10 years experience maintaining the internal CRUD app.