I have been developing the concept of "strategic secrets" to describe secrets that are kept from superiors or outsiders, but that are well known and public within a specific group. My defining example is when someone quits a job: it is common for colleagues to know why he/she quit, but for their boss to be clueless. Many in business dismiss "exit interviews" as worthless. Departing staff typically say they are leaving to pursue new opportunities, or to spend more time with their family. Strategic secrets are secrets only in the sense that none of those in the know have any interest in revealing the truth; they do not think of what they know as a secret. An employee who is leaving will not think it worthwhile to say to the HR office, in the exit interview, that they can't stand working for their boss, or that the hours are too long. After all, they may need a recommendation from that former boss, so want to leave on good terms. They are not going to jeopardize their relationships with former superiors for the sake of a company they are leaving. But their colleagues usually know "the truth."
A good example of a recent strategic secret is the departure of Stephen Emerson as president of Haverford College. He resigned suddenly in July 2011, only four years into a five year first term, and when it was announced, the chair of the "board of managers" refused interviews, but just stuck to a written statement (a clear sign that there was something to hide). Emerson himself is quoted as saying, "I felt my students could use more of my time and I missed not being able to give it to them." He was on sabbatical for the 2011-12 academic year, and now comes the announcement that he is off to Columbia to head their cancer research center. That means he did not spend any more time with Haverford students (except, perhaps, in the lab). Neither Emerson himself, nor the Haverford board, have any advantage in revealing the real reasons for his sudden departure; apparently both decided it would make them look bad. If, for example, he was not very successful in bringing in donations, that reflects badly not only on Emerson himself but also on the board that chose him and monitored him (and that is also involved in fundraising). If there was a difference of opinion on the strategies for upcoming fundraising, or over whether to continue with a high proportion of tenured professors, neither side benefits from this dispute getting into the public domain. By keeping quiet, Emerson has gotten a (good) new job, and the board has gotten rid of him, both as president and as a professor. Keeping quiet served all concerned.
Now if I can only find someone "in the know" to find out what really happened!