“We realized in the fall of 2011 that we could create some potentially useful 2nd screen experiences,” Scott Mirer, director of product management at Netflix, told GigaOm. “At about the same time, we learned that the YouTube team was interested in much the same thing – they had already started to do some work on 2nd screen use cases. And so we approached them on collaborating… We also felt that having two major video services define and promote DIAL would help get it more widely adopted as a common solution to a common problem, vs. taking a proprietary approach. It’s been a productive partnership and we’re confident that we’ll get wider adoption because of it.”
DIAL which stands for 'Discovery and Launch' will let second screen apps discover first screen devices on the same network and launch apps on them. That means that the Netflix app on your phone could discover that there is a Netflix app on your TV and could then launch that app. If you don't have the app on your television an App Store could automatically be launched to let you download it.
New Google TV devices already support DIAL and some 2012 Samsung and LG TVs do as well. More devices that feature DIAL support are expected in the next several months.