Yes. This is a classic use for InDesign Server. (Please note that it's a different product than InDesign Desktop -- and much more expensive).
Hey, first of all nice explanation,
What kind of notification do you need?
SInce you are the one modifying the document, you should already know that you did that. No?
FWIW, I'd probably handle something like this by writing a log of changes to either a text file or a database.
If you need fancier stuff, (again, I don't know what you are after), you might be able to use scripting events to react to certain changes. If that's not enough, you'd probably need to write a plugin which attaches observers which record changes...