I for one would pay for a service that agreed not sell my data and afford me basic privacy assurances. I don't think I am alone in that either. And Whatsapp did have a subscription fee in the past, before it was bought by a dominant player for 19 Billion.

But I can't see why a company like FB would be interested in offering a privacy enhanced version of this service. What could they reasonably expect a user to pay, 10 dollars a month? User data brings in far more revenue than that 10 dollars per user per month. I would think that 10 dollars is peanuts to them by comparison.