Information Explosion

So much has been written about the exponential growth of human knowledge in this "information age" - more books published, massive numbers of websites, etc. We talk about the new skills needed by the internet generation, the "digital natives", skills such as finding information, search skills, evaluating resources, the need to use the worldwide web.

And yet, how is this rise in human knowledge measured? What counts as new information? I've searched, and have yet to find a source that describes any real evidence that humans need to know more now than ever before, or that there is actually more new information than before. It seems that so much of what is published is rehash, remix, mashup, or simply plain old repetition.

I have no doubt that we are learning new things all the time. But hasn't this always been the case? And don't individuals simply have different knowledge than their ancestors? We replace old ideas with new ones, local knowledge with global information. Our brains are much the same size as they've been for millenia, so presumably they are unlikely to process or remember more than ever before. Digital Natives may know the names and hobbies of a bunch of people from Facebook, but is this "new knowledge"?

Has anyone out there got any evidence that the actual quantity of new information is increasing exponentially? Can anyone cite a study that explains clearly what counts as new?

Muisng, musing