Google is rolling out a new feature for Gmail that lets users send and receive emails from unknown Google+ users, even without their email address.

Google is constantly trying to improve its free online mail service and social networking site to attract more users. In a latest announcement from the company's product manager, David Nachum, Thursday, a new feature will be added to the Gmail  service that lets users send emails to other Google+ connections even if the users have not shared their email addresses. The new feature may increase the possibility of spamming, so Google is giving its users the control to choose whether or not they want the new feature added to their accounts.

Google will be introducing the new feature to all accounts over the next few weeks and the default setting will let users send and receive emails from other Google+ connections. The internet giant said the feature would be useful for those who know people in their Google+ connections but haven't exchanged email addresses.

How It Works:

With the integration of the new feature, Gmail users can send emails to other Google+ contacts that they follow on the social network but do not have their email address. The name of the all the contacts will appear as normal when a sender starts typing the first letters of a contact name in the "Send to" field. A new section will show a list of Google+ connections below the usual Gmail contacts for users to choose from.

Senders reveal their email address by shooting out an email, but the recipient can choose to share his/her email address with the sender only by replying.

The emails received via Google+ connections will not appear in the "primary" inbox, but will be placed under the "social" tab.

Google is not forcing its new feature on its Gmail users, like it did with its mandatory Google+ integration for users to comment on YouTube. Users can opt out of the feature with the new setting that will be added to all accounts soon. "Email via Google+" setting offers four options to choose from:

:anyone in their Google+ connections

:users in extended circles

:users within the circles

:And "no one."