What did you do in the very early days to promote the app (apart from Flyertalk)?
until we added messaging nothing I did worked. once we added messaging it took off on its own.
And Q2: when you say "took off on its own" does it mean folks learned about WhatsApp only from word of mouth with no effort from the WhatsApp team?
Q3: what impact did charging for the app have on the company finances and growth rate?
2. yes, word of mouth only... but we helped people spread the word by putting "Tell A Friend" functionality into the app :)
3. it helped us pay for office space, salaries and server bills without eating much into VC or angel money we had in our bank account.