Over the last two days I've been attending and speaking at the TV of Tomorrow Show in San Francisco. One thing said several times is how the "Killer App for TV is TV." This feels shortsighted to me. In the years before touch and gesture we could have said "the keyboard is the killer input mechanism for computing." Before MP3 players and digital music we could have said, "audio tapes are the killer media for mix tapes." Before the DVR we could have said "VCRs are the killer device for recording content." I don't like absolute statements that limit the future solely because we haven't identified or innovated that future yet.
The killer app for TV is entertainment which is subtly but distinctly different than saying the killer app for TV is TV. Today, the entertainment most common to the TV remains largely traditional TV content - whether the content is viewed live or time-shifted, whether it is a DVD, VOD, or delivered in some other physical or digital way. But that also doesn't suggest TV entertainment will always been defined by these content varieties. Just look how home video game consoles have impacted the entertainment consumed on TVs.
Prior to the launch of the original Atari 2600 in the late 1970s the TV was (obviously) not used for video game consumption. Thirty-five years later, much has changed. Today video game consoles are owned by about half of US households. Microsoft has reported 60 percent of xBox 360s are connected to the primary screen and users are spending an average of some 85 hours or so a month on the system. The same thing could happen with the introduction of other technologies that leverage the primary screen. Because TVs are increasingly connected these new services could come in the form of cloud-delivered services and not require the purchase/adoption of a given piece of hardware. Herein lies the crux around the arguments between first-screen and second-screen approaches.
Yes, the killer "app" that has thus far garnered the most traction with consumers is traditional long-form content. But that shouldn't rule out future paradigm shifts. Microsoft's partnership and subsequent experimentation with Nat Geo Wild (early factsheet here) drives this point home by showing how entertainment on the primary screen could evolve with the introduction of new services. I think the killer TV app still lies before us. I'm not convinced it will be an app under the traditional app definition, but I'm equally convinced it could be entertainment in a form different from traditional content.