What is churn?
Churn is quitting, plain and simple. It’s bad, but it’s also inevitable. No one lives forever, no one plays forever, and no game lasts forever. In practical terms, this means that working with churn is all about minimizing it rather than eliminating it completely.
Churn of course hits your bottom line, but it’s different depending on your business model. If you’re running a subscription model it’s very straightforward. You lose X dollars/month if the player drops. If you are running a free-to-play or microtransaction-based title, you are losing the player’s particular spending. And, as most people know, player spending is highly skewed, with a small minority spending the most, and the vast majority spending nothing. As a general rule, you care the most about the “whales” and want to prevent their churn. Social ripple effects (below) are an exception to that thinking.