In the initial wave of guides a decade ago, employers were likely to remind staff that email wasn't theirs as a plaything. In other words, don't write what you wouldn't want to see published.
But these latest guides go farther out of necessity --- social media publishes you all over, and organizations fear their reputations are affected with each Tweet, Facebook post or Flickr stream.
The most recent guides come from the Washington Post, and the response online has been characteristically negative. The Post acknowledges that certain basic privileges are traded when one is a Post journalist. And it demands that its journalists not publish material that might breach standards.
There is also a directive not to associate with or follow those who themselves might breach standards, and that's likely the most contentious of the guidelines, mainly because many journalists use social media as intelligence-gathering and surveillance on others' comments.