> given that anything said by it could be construed as a statement by the company itself.
I don't think this reasoning holds up in this case, given that it was a Yahoo! messenger account with private messages to the employee's brother and fiancee that were in question.
That aside, there are different standards in Europe, IIRC, for things like using work email and network resources for personal use. Most employers I'm aware of don't mind occasional personal use, even while at work, within reasonable parameters (e.g. browsing porn at work probably would not fly at most places, possibly even if it's only on the work network after hours). Many of us posting here now are probably posting from work. Another commenter mentioned that his wife occasionally sends him mail at his work email because she thinks it would be faster or something. All of these would probably be broadly acceptable outside of places like finance or defense contracting that heavily monitor and regulate their networks. I don't think such things are generally considered acceptable in Europe. (I am happy to be proven wrong, if anyone has firsthand knowledge, however.)
I expect my work email to be monitored, because that's how US corporations work. I would never use my work email address to sign up for anything personal and important. I've got a device in my pocket that's linked to my personal email if I want to access something like that at work, anyway.
In spite of my expectation that I'll be monitored using work accounts and on the work network, I still believe people should be told so explicitly. Not only should they be told that monitoring will occur, but they should be fully notified of what is and is not acceptable. This just seems basic to me.
Oh, and BTW, and FYI, it's per se.