All subscription-based apps will soon be required to offer in-app purchases, with a 30 percent cut going to Apple. That means the profit margins for Internet services will get slimmer as consumers are enticed to get their subscriptions directly through iOS. John Paczkowski at All Things D that these apps have until June 30 to provide an in-app purchase mechanism, and, although they can still allow subscriptions outside the app, the pricing within iOS must be equal or better.

Here are five services that could be affected by the policy change:

Hulu

Hulu charges $8 per month for its Hulu Plus service, which extends streaming video access to the iPhone and iPad, among other devices. But Hulu also has to pay for the content it makes available, and that could be difficult if subscriptions coming through iOS result in $2.40 less revenue per user, per month. My prediction: Hulu Plus users will be treated to more ads on iOS devices to make up for Apple's cut.

Netflix