Note: What Instagram refers to as “Disappearing Photos” is what people expect when using Snapchat. Of course, it’s important to point out that once a user presses “post” or “publish” or “send” there is no 100% guarantee that what is shared will not be saved permanently by others. This is true across the web (independent of service) and something that’s important to inform or remind others about.
From the Instagram Blog:
Live video on Instagram Stories helps you connect with your friends and followers right now. When you’re done, your live story disappears from the app so you can feel more comfortable sharing anything, anytime.
It’s easy to go live — just swipe right from feed to open the camera, tap the “Start Live Video” button and start sharing for up to an hour. Your friends may get a notification when you go live so they can tune in. While you’re live, you can pin a comment for everyone to see or turn comments off altogether.
Live video on Instagram Stories and Explore will be rolling out globally over the next few weeks.
Learn More, Read the Complete Blog Post
Additional Details About New Features
Note: All Facebook notes a few differences for these new features for business customers.