I don't think you are getting it -- I am not talking about single user. Whatsapp has 2 billion users, and they are pretty open that they upload entire user's p

I don't think you are getting it -- I am not talking about single user. Whatsapp has 2 billion users, and they are pretty open that they upload entire user's phonebooks to Facebook-owned servers. We know Facebook is not worried much about privacy, so I am pretty sure that this data can be subpoenaed, sold and so on. If you care about privacy, you probably want to install something else, like Signal. But you know what happens if you cannot get all of your friends converted at once, so you keep Whatsapp around? It will keep sending your contact list changes to Facebook, just at it is designed to. Let me repeat this: you worry about metadata, so you want to chat to a friend via Signal. But the moment you add them, this is reported to all other apps including Facebook's Whatsapp. And there is no way to opt out of it. How can people not notice this? How can any company call themselves "privacy friendly" and do this stuff?