Every five or so years for the past two decades the introduction of an Internet connection to a new device type has created a boom in disruptive businesses. Most of these booms—computers, followed by mobile phones, gaming consoles and now tablets—have been clearly successful. Others (remember the Network Computer?) have been ill-timed. Now manufacturers, and a growing ecosystem of partners to support them, are betting big that consumers are finally poised to accept an Internet connection in their most cherished living room technology mainstay, the television.