Sketchnotes are purposeful doodling while listening to something interesting. Sketchnotes don't require high drawing skills, but do require a skill to visually synthesize and summarize via shapes, connectors, and text. Sketchnotes are as much a method of note taking as they are a form of creative expression.
From Mike Rohde's The Sketchnote Workbook:
Friends in the sketchnoting community constantly share how they use sketchnotes to document processes, plan projects, and capture ideas in books, movies, TV shows, and sporting events.
Craighton Berman at Core77 does a nice job of describing sketchnotes as:
Through the use of images, text, and diagrams, these notes take advantage of the "visual thinker" mind's penchant for make sense of—and understanding—information with pictures.
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