i have spent way too much of my adult life in workshops. This has sometimes required spending whole days in windowless rooms with large bits of white paper. (And either you are trying to sort out a huge strategic issue without access to either enough data or natural light… or rehashing predictable answers using large pens to write up very large bullet points). Some recent work on visual thinking arrives like water in a desert.
David Armano has an excellent introduction to both the importance and a start to Visual Thinking on slideshare -
I have found this approach increasingly important in qual, especially as we research experience rather than product. My training focussed on understanding psychological drivers, working with body language and interpreting language. I think it’s not only important to be storytellers, but also to be able to create and use diagrams to clarify thinking during the analysis process, both as individuals and as part of a team.
Dan Roam’s “The Back of the Napkin” is a small book i have been carrying around with me recently. (And it’s not just because he introduces visual thinking by comparing it to playing poker). 
It’s easy to read, provides illuminating examples and demonstrates that you don’t have to be an artist to utilise the power of sketching diagrams. His website has some great resources including some downloadable tools such as The Visual Thinking Codex, and The Visual Thinking Toolkit.
And finally a practical hands on resource is Fundamentals of Graphic Language is available from Grove Consultants. 
“History of the Internet” is an animated documentary explaining the inventions from time-sharing to filesharing, from Arpanet to Internet.
The history is told using the PICOL icons on picol.org.
History of the Internet from PICOL on Vimeo.
