Kathy Shaidle has an email exchange with Seth Godin, [email him]who replies to her with an email which has this tacked on to the end:

This note is off the record (blogs and tweets, too) unless we agree otherwise.

Kathy complies, although she's not not naturally a compliant person, and simply posts her reply:Shorter Seth Godin: 'It's only screaming when other people do it'

I remember the late Cathy Seipp's attitude to this kind of thing—she had a short way with it, and I think David Cay Johnston must still wince when he thinks of what she said when he tried it. She wrote that

Over the years, various journalists — such as Alex Beam of the Boston Globe and Nikki Finke of the L.A. Weekly — have sent me emails that basically say this:

"Hello. Although you have not asked for my opinion, I would like to tell you what I think of you. But I suspect, on some level, that this makes me sound like a pompous git. So you are hereby ordered to keep my insults to you secret. If you disobey, you have violated our non-agreement and are therefore unethical.[http://cathyseipp.journalspace.com/?entryid=704 no longer online, but reproduced :here]

See also here and here. Journalists can agree to go off the record, but other people can't impose that duty on them, just by including it in an email.

Miss Seipp explained this, saying

Confidentiality asked for, and not granted. An off-the-record agreement has to be AN AGREEMENT. I feel no obligation to obey instructions that I keep unsolicited advice secret. I give non-journalists a lot of slack about this, but not journalists. You should know better, and if you don't, tough.

and concluding

"And I'll tell you something else you can forward to any interested parties awaiting your opinion before you roll it up and stick it up [your a**]," I added. "When journalists go from keeping secrets about their sources to expecting sources to keep secrets about THEM ... then something in the press has begun to stink with self-importance...you might consider spending some time pondering that."

That being said, at VDARE.com we have a policy of asking people for permission before we post any friendly email they send, because leftists will try to get people fired from their jobs for associating with us. But that doesn't apply to attacks from the Great And Good in the media.