@briankrebs You can add Viber to that list! I blocked it from accessing my Android contacts, and yet within seconds of providing my number (and no other details yet, not even name or photo, hadn't finished signup), I started getting Viber messages from old friends who have my number.

Viber insists they don't upload numbers and that what I describe couldn't have happened. Never figured who to report that privacy breach to... but it wouldn't get anywhere anyway, right?