New times demand new conventions. In a world where twitter and facebook and blogs can spread an idea around the world in a few seconds, how do you have a conversation with someone in confidence?
Just say NFYB ("not for your blog.")
Just like safe sex, it might not be romantic, but it's something we need to talk about. So talk about it. The presumption is rapidly changing. It used to be that all emails or whispered hallway discussions were 'off the record.' Now, more and more, there is a bias to post/twit or share. "NFYB" clears the air.
When everyone is a journalist, most things are on the record.