Facebook has never really been known to just let companies develop independantly, and they paid that much money for a reason: integration. I've never used WhatsApp, nor do I know the story on what happened to it, but I doubt the Occulus Rift will be the same as it would've if it were developed independantly. The two main things I fear: tons of "farmville" type games for the Occulus Rift flooding our news feed, and the lack of privacy they're known so well for. We just have to wait I guess.