I have to imagine that these speculations would be most applicable to roles where contacts and networks are most valuable, like business development and sales. Bear in mind that as far as I know, no one has or is testing this specific issue in court. This is just the reasoning on a particular lawyer. It makes a certain amount of sense but only cause for concern for people who are probably already well aware of the value of this data to their employer. I doubt someone who just uses these network sites for friends and family has anything about which to worry. Don’t be fooled by anyone who tries to simplify this down to just an issue of using your employer’s time or even their network connection. I would have to guess that the value of the data is much more at issue to the relevance of this thinking.