Sociolatte

Google+ hangouts on air are a little different from normal Google+ hangouts. Normal hangouts are for friends, colleges and families to have live face-to-face discussions. Hangouts on air however are for live broadcasts to the masses. With hangouts on air any number of viewers can join in, the President of the US has used this functionality thrice. So, Google+ hangouts on air just got a whole let better. Let's say your really engrossed in watching a hangout and suddenly you need to go somewhere for some quick work, maybe need to use the loo. Come back soon after and just hit the rewind button to where you left off. Your hangout will now start playing from the time you left off.

All recording from Hangouts On Air will be available on YouTube right after the hangout. So if you missed it, you can see the whole thing on YouTube right-after. Also the quality of video for mobile devices just got better. So if you're on-the-go, you can expect some better quality videos from Google+. If you're conducting a hangout on air - live broadcasts will start without the need to press the refresh button. The grayed out ( start broadcast) button will turn red as soon as the show starts. These are all parts of the new improved Google+ Hangouts on Air announced by Google+.

Source: Google+ update.