WhatsApp scaled to 1B users with only 50 engineers
While what you says about focus is important, I've seen plenty of focused startups die.<p>WhatsApp had success because they executed well enough at the right time.<p>I hate WhatsApp with passion because of its limits and that horrible web interface that needs your phone connected in order to work.<p>I know plenty of people (me included) who stopped talking with some groups of people because they didn't tolerate WhatsApp.<p>It's mediocre software at best, but because of the network effect and first mover advantage, that was enough.