In the Twitter/FB/Gmail reading applications, you should default to only showing the user content that has Privly-type links. The best way to do this is to display any content that contains the word "privly." Since the users are unlikely to have any content when they first install the application it may be necessary to define filler content that will not be shown as soon as the app has real contents to display. I suggest showing a fake Tweet/Message/Email that gives the user information about the application.