It amazes me in this day and age that people don't realise that anything they say on these systems can be dug out and read by anybody, anywhere at any time ...
I do. I've only ever worked for public universities or state owned organizations, so every work email I've ever written is theoretically accessible via an open records request. I write every email as if it's going to be published on the front page of my local paper.
> If I'm typing it I'm checking myself just as if I were speaking across an open plan office.
I do this, too. I would call this good manners. But that's wildly different from being aware that the contents might be used in discovery or being published out-of-context. Especially the latter provokes the Richelieu citation.
I'll echo the other comments here, too. I never put anything in writing that I'm not comfortable being published publicly. Working in the public sector and being subject to public records requests, and working in the private sector and having my emails quoted by opposing counsel to a judge during a lawsuit both taught me the value of being exceedingly careful in what I write.