NO INTERFACE has been recently mentioned as an emerging trend in user interface design. With the rise of devices with minimal to no screens at all, It's worth pointing out how the Apple Watch fits in that paradigm.
One of the greatest features of the Apple Watch is that the phone ring is no longer needed. With the new Taptic Engine any notification becomes subtle but noticeable - unobtrusive but obvious. And most of this can be done without any new code. With the Taptic Engine, I can receive a slight series of taps on the wrist when a phone call comes in, a new email is received, or a new text message comes in. I don't need pull my phone out and check it every five minutes. I don't need to interrupt an important meeting with an annoying phone ring of some new direction song.
It isn't just the way you touch the screen but how you touch. Force Touch is a great feature which Apple has introduced in the Apple Watch and are now introducing in their other hardware. Force Touch is used mainly as a "right-click" or context menu on the watch. But really touch is just the very edge of being truly No Interface. If you look at where the video game market has expiermented, you see where gestures can really go. The Wii and the Kinect are only the beginning of where gestures could be headed. With technologies like Microsoft HoloLens and Facebook's Oculus Rift we'll see even more devices where gestures along with virtual and augmented reality make screens unessesary. My hope is that the new Watch API will open even more gestures to developers.
When people ask how ordinary people can really utilize such a small screen, they fail to realize how important speech is. That is one of the first things I noticed. With products like Amazon Echo making speech the preeminent interface we can see how voice commands no longer demand an intense screen based experience.
Siri, Apple's speech based intelligence interface, is used throughout the Apple Watch and at least for me Works surprising well. Apps like Amazon and Evernote also use it for product searching and note taking respectively. With WatchOS 2 coming soon, we know the use of speech will be expanded further with the built-in capability of the OS but also for developers as well.
Apple sees the watch as the beginning and the playground for testing out many of the principles of No Interface. Hopefully WatchOS 2 will expand on that further for users and developers alike.