A good friend is explicit about the level of confidentiality of information that he shares. The three levels he uses are:
(1) Okay to share with close friends
(2) Okay to share with your wife
(3) Forget it as soon as you hear it :-)
While levels (2) and (3) typically elicit a smile, I’ve come to appreciate the wisdom in this approach. It is far better than the generic “please don’t share” because we hear it deployed far too often with varying standards.
It helps to be specific about the confidentiality we expect.
And, when in doubt, it is good practice to ask.