“Consumers flock to best of breed and they learn and decide what best of breed is because other consumers tell them. Word of mouth is such a dominating channel. Flo is really special — they get over 50% of their users are organic. Moms now are telling their daughters, friends, girls in school tell each other about it.”

Category killers win on organic word-of-mouth — over 50% of Flo's users are organic

In consumer, word-of-mouth is the dominant channel — not paid UA. The apps that become category leaders reach a self-reinforcing flywheel where organic referral dwarfs all paid channels. Crowley's framing: 'category killers' emerge in every vertical (female health, youth sports, family management) and they compound on the organic advantage until paid acquisition becomes almost irrelevant. Building for that scale is the highest-value strategic goal.