A culture with focus on openness

At a recent seminar here in Switzerland, I asked the participants the following question: What would you point out as the most important value for how we are going to work together? After reflecting individually about the question for a couple of minutes, several participants wrote down the value openness. In fact, openness was the most frequently mentioned value.

This focus on openness corresponds well to what the new CEO of A.P. Moller - Maersk, Mr. Nils Smedegaard Andersen mentions as being of importance. Source.

In your opinion, what does it mean for a company to be open? In other words, what should employees/managers do to live out the value openness?