I've had a lot of success on FB mobile install ads.
What GP is talking about is the much sketchier model of blocking (or greatly slowing down) access to an app unless the user goes and downloads an affiliated app. This is artificial download inflation by bending the user over a barrel, not advertising.
More commonly this is done by IP tracking.
- Device taps on button/ad in app A to download app B.
- URL is specially encoded to identify app A.
- Server registers some unique information about the device.
- Server redirects to app B's app store page.
- User downloads app B.
- User launches app B, which reports back to Server. Server recognizes device and is able to associate this install event with the original tap from app A. App A's servers are contacted to this effect.
The trick here is that the uniqueness of the device here is pretty limited and temporary. If the user downloads app B, then does not launch it, their IP address will soon change (cellular networks and the such). It's not a foolproof system.