I find it really useful to write and draw while talking with someone, composing conversation summaries on pieces of paper or pages of notepads. I often use plenty of color annotation to highlight salient points. At the end of the conversation, I digitally photograph the piece of paper so that I capture the entire flow of the conversation and the thoughts that emerged. The person I've conversed with usually gets to keep the original piece of paper, and the digital photograph is uploaded to my computer for keyword tagging and archiving. This way I can call up all the images, sketches, ideas, references, and action items from a brief note that I took during a five-minute meeting at a coffee shop years ago--at a touch, on my laptop. With 10-megapixel cameras costing just over $100, you can easily capture a dozen full pages in a single shot, in just a second.
Dude's a bit of a nutter, don'tcha think?