1) The document discusses how network properties like strength of connections, number of connections, and threshold to forward can be used to understand social media, epidemics, the brain, and other complex networks.
2) It provides examples of how social media companies can design their platforms to leverage these network properties like increasing strength of signals, number of connections, and lowering thresholds to forward.
3) The goal is to better understand how information spreads in networks and use that to improve viral marketing and user engagement in social media.