“There are certain notes in your Second Brain that are disproportionately valuable, that you will nd yourself returning to again and again. These are the cornerstones of your work on which everything else is built, but you can’t usually know which notes are cornerstones up front. You discover them by sharing your ideas with others, and seeing which ones resonate with them. It is by sharing our ideas with other people that we discover which ones represent our most valuable expertise.”