DIAL—for DIscovery And Launch—is a simple protocol that second-screen devices can use to discover and launch apps on first-screen devices.
Tablet, Phone etc. TV, Set-top box, Blu-ray etc.
For consumers, DIAL removes the pain of having to launch the required app on the first-screen before interacting with it from their second-screen. DIAL does not have any significant impact on the second-screen's battery life and the only requirement is that both first and second-screens are connected to the same home network.
For device manufacturers, DIAL increases usage of applications on their first-screen products (TV, set-top, Blu-ray, etc.).
For app developers, DIAL helps link their second-screen app to their first-screen app without requiring a manual launch or pairing process by the user.
See the DIAL Protocol Specification for more discussion of typical use cases.