"A state where a positive or negative feedback loop is feeding on itself and accelerating from it’s own momentum. How it’s useful Flywheels are a related concept to feedback loops, but are important for managing platforms and marketplaces. For example, imagine you run Apple’s iOS app platform. You have two users: app developers, and app users. The flywheel is the phenomenon where more app users attract more app developers (because there is more opportunity to sell), which in turn attract more app users (because there are more apps to buy), which in turn attract more app developers, and so on. As long as you nurture the flywheel, not only will you grow, but you’ll grow at an accelerating rate. If you’re managing a flywheel, you have to do everything you can to keep it spinning in the positive direction, because it’s just as powerful the other way. For example, if there are so many apps on the platform that new apps can’t get discovered anymore, app developer growth will slow and break the flywheel — you need to solve that. " — Brandon Chu
Product Management Mental Models for Everyone