I'm not so sure about the implicit assumption that growth/phase change should be measured by head count. Sure you need some estimate but I do find the stage3 =

I'm not so sure about the implicit assumption that growth/phase change should be measured by head count. Sure you need some estimate but I do find the stage3 = 400 employees a bit strange. Especially given WhatsApp happened. I would have preferred if the article used some other measures to indicate the state changes (profit, net promoter whatever) or at least discussed this a bit more. That being said it's a pretty good article. I think it makes the product/market fit -> company building shift pretty clear.