Google explains the features of Android Wear at Google I/O 2014

Three months after its initial announcement, Google finally expanded on Android Wear, its smart wearable platform that will strive to dominate the smartwatch market. Recognizing that style is as important as functionality, Wear supports both square and round screens. They will be always on screens too, in power-saving mode most of the time and in full color when you raise your hand.

You will of course have your pick of beautiful watchfaces, but the power of Android Wear is in the wealth of notifications it can provide. It pulls notification from your phone and you can tap each one to view more info (each notification has a cool background that slides in with the new Material design UI). If you swipe a notification away on the watch, it goes away on the phone too.

The full SDK for Android Wear has now been released, so devs can write apps that run on the smartwatches themselves. When you install an app on your phone, the smartwatch portion will automatically be pushed to the watch, so you don’t have to do two installs either.
You can use voice commands with the simple “OK Google” prompt to add contextual reminders. If you set up a “when I get home…” reminder the phone will bring it up as soon as you get home. Apps can also learn from you – your smartwatch can remember when you hunger for some pizza usually strikes and it will show the pizza order UI so you can bring the order time to a minimum.

Wear also features a Do not disturb mode too, you just swipe down from the screen. Swipe down again and you are getting all your notifications.