The first thing that popped up in my mind is: do you really need to do that?
You state that keeping an eye on things are a large part of your duties. Perhaps there's a cultural difference thingy going on, but I'd get very nervous if my manager would keep looking over my shoulder that way. Doesn't s/he trust me to do my work right?
The way I see it, assuming you're managing professionals, the role of the manager is to tell the professional what should happen and then facilitate the means to do so. The role of the professional is to do her work to the best of her ability, within the constraints set by the manager. This leaves the manager time to think up a vision and think about how to bring it about.
Again, this is (a) without any knowledge of the background; you may have very good reasons to want to keep an eye on things. And, (b), it may be a cultural difference. As I understand it, we Dutchies tend to treat management orders as suggestions, causing no end of headaches within US HQ's.
More practical, but somewhat in line: I suggest that you follow Kelly's suggestion and treat them as Waiting For's; also, I suggest that if you have the space you store the entire conversation as a conversation thread, if your mail app allows (and if not, better change). That way, if you need to be brought up to speed on a particular subject, you can simply trace the whole conversation backwards and debug what's gone wrong.
Hope this helps!