In the ideal media world, ad-supported products are able to compete with paid rivals because people are willing to put up with a little inconvenience in return for getting something for free -- as long as the products are otherwise functionally equivalent. But if the ad-supported version actually ends up limiting your ability to consume other kinds of content, or even just use of the device itself -- well, that could be a problem.

No, this is not an April Fool's joke. Total revenues from mobile apps are on track to reach $99 billion by 2019, according to a new forecast from Juniper Research.