You know, since I heard the news I kept hearing people make that argument and I thought, "But Whatsapp and Facebook are completely different products and markets." ... And then I realized that the only thing I use Facebook for is keeping in touch with people. And Whatsapp could easily fill in for 80% of what I do on Facebook. Indeed, they are trying to neutralize competition.
Sadly, I remember the days of Microsoft's near-monopoly on desktop computing, and I'll be getting rid of whatsapp within the week. On to Telegram or whoever is willing to make an identical app that isn't owned by FB or Google or whoever. The question will be whether I can convince others to switch.