AARRR – Pirate Metrics – is a popular metrics and analytics framework for online startups developed by Dave McClure, the founder of 500 Startups.
It is based on the assumption that every startup needs to get customers through 5 key stages (AARRR):
Acquisition: users come to the site from various channels
Activation: user enjoy 1st visit: “happy” user experience
Retention: user come back, visit site multiple times
Referral: user like product enough to refer others
Revenue: user conduct monetisation behaviour
The method is explained in more details in this video: