One of Google+’s best features are Hangouts, but you don’t have to be a user of the social network to utilize one of it’s best features. Google is beginning to roll out Hangouts in Gmail. You will then be able to video chat to users on their mobile phones running either Android or iOS as well as other computers.
Unlike Gmail’s old service, “Hangouts utilize the power of Google’s network to deliver higher reliability and enhanced quality”. However, if you aren’t a member of Google+ you will not be able to watch cat videos on YouTube with your friends or chat with up to nine friends.
(Source: Gmail Blog)