Android already powers a number of smartwatches, but now Google announces a version of OS tailored specifically for such devices-- the perhaps self-explanatory Android Wear.
As seen in a typically slick demo video, Android Wear pushes location-based data from smartphones to smartwatches together with the usual bevy of message and social network notifications. It features a Google Now-style UI users and allows natural language input via the "OK Google" prompt.
According to Google it also handles functions such as health tracking and connectivity with other devices, such as summoning a playlist from a mobile device or pushing a video to a TV, while being extremely power efficient.