@dawoel,
A little silly but I like it.
Point 1)
If A and B are speaking and A says phrase X it could convey quite a bit of information. If A says X to C, it may simply confuse him and thus give no information. If A looks a image Y, it may give him only superficial understanding or information. If C looks at Y it may give him a deep understanding.
It is all about context, both present and past.
Point 2) How do you think we should go about measuring how much information has been taken in? Certainly this is needed to really answer the question in the obvious way.