First out of WWDC today were updates to watchOS. watchOS 4 will provide new watch faces, one of which will be powered by Siri intelligence. This will all be part of a free update this fall! The Siri face provides data that changes as the day progresses, with a rotation of the digital crown providing a 3D-list of what's been going on.
There are more faces that will show up; a fun Kaleidoscope face that uses images to create a moving kaleidoscopic image, and new animated Toy Story faces. The Activity face now provides coaching, letting you know when you're getting near a goal to give you a "nudge" to keep moving. Apple's also going to provide workout challenges that are tailored to your current activity, and will provide much more exciting celebrations when you reach a goal or make a challenge.
It's also possible to add workouts together -- doing training for a triathlon, for example, you could start with a run, then immediately follow up with a bike ride, then finish with your swim.
Apple also announced that many major gym equipment manufacturers are planning on supporting Apple Watch two-way syncing. This ensures that both devices see the same results in terms of calorie burn and "mileage"; expect to start seeing some of those home and professional gym devices later this year.
The Music app will now automatically sync music to the Watch, and the device will support multiple playlists -- perfect for listening with Apple AirPods.
Best of all, there's a new scrolling app Dock that appears to make selecting apps a lot easier than searching all of those tiny round icons.