Hangouts on Air was launched on 20 September 2011 along with the public launch of Google+, but it was only made available to a limited number of broadcasters.This opened the Hangout to any number of viewers and also recorded and automatically published the stream to YouTube.
Broadcast publicly. By checking "Enable Hangouts On Air," you can broadcast your live hangout—from the Google+ stream, your YouTube channel or your website—to the entire world.
See how many viewers you’ve got. During your broadcast, you can look inside the hangout to see how many people are watching live.
Record and re-share. Once you're off the air, we’ll upload a public recording to your YouTube channel, and to your original Google+ post. This way it's easy to share and discuss your broadcast after it's over.
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