They seem to have increased restrictions on purchases outside Apple's control (section on 'Purchasing and currencies').

    Subscriptions Outside of an App
    
    Subscribers to magazines, newspapers, books, audio, music, video 
    and cloud storage services who were acquired outside of your app
    can read or play content through the app. However, you may not 
    provide external links in your app that allow users to purchase 
    subscriptions outside of the app.

Sure, they've created the OS, but this is starting to feel a bit like a troll guarding a bridge, forcing every one to pay up to walk across.