"It's not as though an NC-17 rating on the App Store really causes any problems for a developer unlike a movie getting an NC-17 rating which is a big deal still."

I wonder about that.

I wrote the Nihongo app, which, like NinjaWords, kept getting rejected until I finally set the rating to 17+.

When it was finally in the AppStore, friends told me that an "are you sure, since this app has Frequent/Intense Sexual Content or Nudity and Frequent/Intense Mature/Suggestive Themes"-type warning came up just before they hit "Buy".

I wonder how many people hesitated or declined to buy the app b/c of that.