Quoting from Transmedia vs Multi-screen Distractions — by Michael Matthews at Forbes.com — which provides an example of how multiple devices are starting to work with each other:

In Canada, the Food Network and Paperny Films integrated mobile strategy into the release of a new TV series called Eat St. The TV show launched simultaneously with an iPhone app of the same name. The app offered location-based services linking users to vendors featured on the show as well as thousands of others across North America. The app gives fans a deeper experience — they can find carts in their cities and begin accessing them. This digital integration worked two ways: fans of the app could check out the TV show, and fans of the show were introduced to the app.