Came across a few other pieces of seemingly related stuff on the net, particularly wikipedia; haven't had a chance to cross check with the original sources yet.
Alvin Toffler has used the term Information Overload and might be the person to popularize it. The idea has been around for sometime.
Infact, Steve Beller has linked information overload to stress.
To get an idea of the volume of information we are talking about, I find the How Much Information project site particularly informative.
However, I feel information overload has been concerned with information that has been processed to some extent. So people actually read stuff but fail to comprehend or verify its truth and therefore can't use it, but have to store it and the conflicts arising out of this leads to stress. I think I believe that the effect is much more subtle. If noticing something versus reading something can be distinguished as conscious and subconscious processing, then I feel subconscious processes are capable of initiating the biochemical cycle (hopefully this is known and I'll be able to find a scientific reference to verify); I also don't think that only the subconscious information leads to stress and the conscious mind is the equilibrium state.
By the way, looked up Alvin Toffler because he was quoted by Carolyn W. Meyers in MRS Bulletin vol 31, Jan2006, p5-9 to say that the illiterate of th 21st century are not those who can not read or write but those who can not learn, unlearn and relearn.