Source: How to Model Viral Growth: The Hybrid Model | LinkedIn
Growth is the most important thing...
And the followup:
Pinterest Growth Hacks: How did it grow so fast? « Adam Breckler
Growth hacking: leading indicators of engaged users
Eliminate ego, don't focus on k, and understand engaged users - Growth according to Chamath via Sandi MacPherson - QUIBB
5 Undercover Growth Hacks, You Wish You Had Thought Of