Definition
Activation rate is the percentage of new signups in a cohort that reach a defined first-value event within a set time window. It answers a single question: of the people who arrived, how many actually got the product to do the thing it exists to do?
Unlike revenue or churn, activation is not given to you by the world. You invent it. That makes it powerful and fragile in equal measure, because a badly chosen activation event produces a number that moves convincingly and means nothing.
