Google is tightening integration of all of its services by allowing Google+ users to email each other without knowing their email. By default, emails are hidden until you send someone an email, revealing your email, or when someone replies to you, which reveals their email. It’s a bit confusing but the feature can be tweaked or turned off completely.
Google’s reasoning behind allowing Google+ users to email one another without having exchanged emails is that people often meet but forget to exchange emails. This allows Google+ users another avenue to reach a person. While Google+ users can share privately to a single person or group of people, the social network has no traditional direct messaging function. Google+ integration into Gmail is one way to make private messaging easier to use.
This new feature works with Gmail’s new inbox categories so you can file interactions with other Google+ users under the “Social” tab.
If you want to disable the feature entirely, head over to your Gmail settings to find the drop-down menu next to “Email via Google+” and select “No one.”
Source: Official Gmail Blog
