Churn
Red Queen Effect · Red Queen's Race
An evolutionary hypothesis which proposes that organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in a constantly changing environment.
Origin
The exact origin of the term as a business metric is disputed, but it emerged in the telecommunications industry during the 1980s and 1990s as mobile and long-distance carriers began tracking subscriber loss. The word draws on the older mechanical sense of "churn" — the violent agitation of a butter churn — to evoke constant customer movement in and out of a subscriber base. By the mid-1990s, companies like AT&T were treating churn rate as a key performance metric, a practice that spread across SaaS and subscription businesses in the decades that followed.