My team knows to have scratch paper handy when I am around. At home I have stored the back (empty) ends of used notebooks from friends and family. This is because I draw a lot. I think when I draw. On good days, I am able to put my emotions into pictures. On other good days, I can put my thoughts into pictures. And these thoughts are those best communicated with others. I believe the reason for this is because many people think in pictures, as I do.
Remember in school we learned that there are three kinds of learners? Visual, who learn by seeing. Audio, who learn by hearing. Thirdly, kinesthetic, who learn by touching or doing. I remember that everyone learns via two of these (I am strongly visual and kinesthetic. That is why I will remember faces but not names--unless I write them down). The majority of people will be visual and something else. Visual and audio, or visual and kinesthetic. That visual part is very important to us and yet I do not see us moving to pictures in all aspects quickly enough. But we are getting there.
Evidence is Steve Jobs' presentations. Evidence is the rising popularity of BPM GUIs. Evidence is Ubuntu. Evidence is PoP Project (did you catch the plug?).