The question is why there is so much talk in these last three or four years about information visualization and about the computer support of this cognitive activity. There are several reasons: one is that in the last decade everyone of us saw that the amount of data we have available now with computers increases at incredible rates, so ten years ago having a mass-storage device of 100 Gigabytes was a privilege for a few scientific researchers. Nowadays, everyone of us can buy a 100 Gigabyte hard disk and install it on her own PC at home.
So nowadays everyone of us has incredibly large datasets available, if he or she needs them. But we are not capable, we are limited as human beings in our cognitive and perceptual abilities, so we have lots of data, but we are not able to browse through thousands of screens, of numbers, of symbols and make sense of all these large datasets we have available.