Editors' note: This post was updated July 16, 2013, with more information.
Having the app on your home screen gives you immediate access to one-on-one and group video calls formerly found by going through a couple of menus in Google+. With Hangouts, you can have a video call with up to 10 people and you can choose who will be in the hangout through a list of your contacts or by using a search field. During your hangout, the app automatically detects and displays the person who is currently talking, with smaller live shots of the other people in the hangout across the bottom. You also have buttons across the bottom that let you switch between your front- and rear-facing cameras, turn off the camera or microphone, and quit the hangout.