The Pirate Funnel is a framework to cut a company in pieces and shows you where to focus your attention. The framework was developed by Dave McClure and called the Pirate Funnel because the first letters spell out AAARRR for Awareness, Acquisition, Activation, Retention, Referral, Revenue.
There is a wide variation of how companies acquire customers. It is critical to tailor pirate metrics to match your specific circumstances.