Hear your selected notifications throughout the home
Turn your speakers into an intercom system
Automatically enables when home and disables when you leave
Quickly get to intercom from home screen widgets
Broadcast to your home from anywhere in the world
Customize broadcast with custom tones
Check out this video
Only Sonos speakers. Contact your speaker manufacturer if you'd like your speaker to be supported as well.
Yes as long as the original source was started from Sonos app.