Startup Metrics for Pirates: AARRR!
Time investment: 6 mins
Aquisition, Activation, Retention, Referral, Revenue.
http://www.youtube.com/watch?v=irjgfW0BIrw
Peter Thiel’s Stanford Startup class notes
There's also a book coming out.
http://blakemasters.com/peter-thiels-cs183-startup
http://zerotoonebook.com/