About Hangouts availability
You can start a Hangout with anyone you want at anytime you want. When you start a Hangout with someone on your computer, you can look at the person's profile picture in your Hangouts list to find out whether the person will be notified about the Hangout immediately or later on.
- Profile picture with a green bar underneath it: These people will be notified about new messages or video call invitations immediately. For people who are using Google Chat, Google Talk, or a third-party chat app, the Chat list will show people who are available with a green dot next to their name.
- Profile picture without a green bar underneath it: These people are likely on a mobile device, have Snooze Notifications enabled, or are idle on their computer. They will be notified about messages and video call invites, but they may not see it immediately. For people who are using Google Chat, Google Talk, or a third-party chat app, the Chat list will show people who are idle with a yellow dot next to their name.
Other status options not available in Hangouts, but still available in Google Chat
- Invisible: You can't set an invisible status in Hangouts, but you can revert to Google Chat to use it. When you set your Google Chat status to invisible, Hangouts users will see your profile picture without a green bar underneath, indicating that you may be idle on your computer.
- Custom status message: You can't set a custom status message in Hangouts, but you can use it in Google Chat. If you set a custom status message, only Google Chat users will be able to see the custom status.
To temporarily disable notifications of messages or calls for a while, you can snooze notifications. People who send you messages or invite you to video calls won't be notified that you have snooze notifications turned on. But they'll see your profile picture without a green bar beneath it, indicating that you might not be immediately available.