I don't mean to a naysaying generalist, but does anyone pay a great deal of attention to the level of urgency applied to a particular message?
I work in a large company (>4000 employees) that's in several countries and I receive dozens of emails a day. A few are marked urgent but rarely is the message all that urgent. I understand that the sender believes the message is urgent but I would expect that most people, as mail recipients, prioritize messages based on who sent it, the subject matter, or the applicability to a current project or issue. I'd be willing to bet one will read a message from their boss, spouse/significant other, or best friend much sooner that any message marked Urgent or Important.
Some senders mark more than half their messages to me Urgent...that's not very likely. Whether the time zone is France, China, or U.S., one should use the phone if the message is that important.
If setting the priority of a message is important, do people use "Low" all that often? I've seen only used by one person, and in-house lawyer. It's kind of funny to see actually.