About the people widget
Email is just as much about the people you communicate with as it is what you’re communicating about. The Gmail people widget, located on the right-hand side of your messages, shows you contextual information about people you’re interacting with in Gmail.
You can communicate with individual contacts easily through the people widget, or just use it to find basic information. Simply click on the contact’s name on the right side. From there, you’ll see:
Information about your contact, which may include information such as their name, email address or occupation. This information comes from your account’s Contact Manager.
Google uses information from your Contacts Manager, the email thread that you’re reading, or the user's email address, to determine which name to display in the widget
Recent Google+ posts your contact has made visible to you, which you can +1 directly in Gmail
Recent email your contact sent you
Thumbnails of recent photos your contacts sent you
Google Calendar events if your contact’s Calendar is shared with you
Google documents shared with both you and the contact
You’ll also be able to easily email, chat, or call your contacts using the call phones in Gmail feature, or edit contact details and settings. If you're using Google+, you'll be able to add the contact to your Google+ circles.
If you have several contacts on an email thread, the contact with the first unread message in the conversation will have the above information shown in the people widget. You can find more information about others in the conversation by clicking the ‘more’ link at the top of the people widget. On a thread with many recipients, contacts are listed in order of who last responded on the thread, who is currently online and available to chat, contacts that whose chat status are set to ‘Busy’, contacts whose chat status are ‘Idle,’ and then contacts who you haven’t yet invited to chat before.
You can also interact with the whole group by using features like:
Start a group chat
Schedule a Google Calendar event with this group
Compose a new email message with all recipients on the thread
If you ever decide you don't want to see the people widget, you can do so by doing the following:
Click the gear in the top right .
On the General tab in Settings, select the ‘Hide the people widget’ radio button.
Click Save Changes at the bottom of the page.