I’ve tried to be more open about my salary, even with co-workers. If asked, I will tell, but I don’t volunteer it. The thing is that this information is that keeping it secret ONLY helps the employer. Maybe if the average worker was more open about it, we would have the kind of wage growth that we’ve been lacking. As a side note, I think people in rapidly developing countries do share their salary and that’s one of the drivers to wage growth.
As an aside, Ontario passed the Public Employee Salary Disclosure Act in 1996. This requires that the government of Ontario publish the salary for every provincial position. This includes by name for people who can negotiate their salary. The result has been huge salaries in the public sector there because everyone now does go to their boss and say, “I need more than Mrs. X because …”.