“What you charge for is things that break the rules of the game that if everybody were doing them it would ruin the experience across the ecosystem but if a few people were doing them you would generate revenue and it would create an honest balance a more honest balance in the ecosystem.”

Paywall Design as Game Theory: Charge Only for Behaviors That Break the Ecosystem

Phil Schwarz describes Tinder's paywall philosophy as pure game theory: unlimited right swipes degrade match quality for everyone, so limiting free swipes and putting unlimited swipes behind a paywall simultaneously improves ecosystem health and generates revenue. Passport (location-change) worked the same way — fine for a few travelers, destructive if universal. This framework transfers to any two-sided or network-effect app: find behaviors that are fine at low frequency but harmful at scale, then monetize them.