The Alarm.com app will let you look at video cameras set up around your home.
With Instagram on your Apple Watch, you can view the latest photos from your friends, like photos, and make comments.
The Shazam app will let you have your Apple Watch listen to the music that's playing right now so you can identify the artist and purchase the song straight away.
When you need a ride to the airport, the Uber app lets you quickly contact a car near you, tells you the model of the car so you'll see it, and gets your driver to you without ever taking out your iPhone.
The WeChat app will let you chat with friends and family, and the ability to add stickers was demonstrated on stage at the event.