There's a good chance this is where the interoperability comes into play. They might not be able to track direct communications but people will still interact with public content on places such as Instagram. As soon as accounts are linked they'll be able to advertise in places such as WhatsApp based on likes in Instagram.

They can still target ads, just not on the content of the messages. A lot of people put their birthdays and genders and like lots of brands on Facebook.

That is a really good question - whats more likely, they fully pivot and really don't gobble up all this user data and keep conversations private and take a hit on mainline revenue, or they SAY they're going to do this stuff, release something that looks slightly more private but don't do any of it?

The market right now isn't shook at all, no change after hours. If it had anything remotely to do with the magnitude of what they're suggesting the stock would be down quite a lot.

Do you think this privacy-oriented platform will be free?

I think it'll be: free Facebook is old Facebook (we will own your data) .. profit-Facebook is new Facebook (pay us to keep your secrets) ...

This isn't going anywhere :

People that don't "care" -in the sense HN does- about privacy will stay in the free tier. Why should they pay now?

People that do care have either stopped using the platform or will be not be trusting FB enough to bother.

The obvious way is financial services.