The short answer
Churn rate measures the percentage of customers or subscribers who stop over a given period, typically monthly or annually: cancel a subscription, stop renewing, leave a membership. It is the direct counterpart to growth. A business or creator offering can add new subscribers steadily and still stagnate or shrink if churn is high enough to offset that growth.
Why this matters specifically for a creator membership or recurring offer
A membership community or any other recurring-revenue offer lives or dies on churn as much as on new signups. A steady stream of new members means little if an equally steady stream is leaving each month. Tracking churn, rather than total member count alone, reveals whether the offer is retaining people. Total count can mask that.
High churn is a signal to investigate, not accept
A high churn rate is worth treating as a specific problem to diagnose, asking departing members why where possible, rather than an inherent cost of running a recurring offer. Consistent delivery is what keeps churn low. It is the same discipline that makes a membership community worth joining in the first place.