Open your Gmail account. Click on the gear icon in the top right and select Settings from the menu.
In the General tab on the Settings page, look for the section that says: Email via Google+.
Click on the dropdown menu next to "Who can email you via your
Google+ profile?" You can pick one of four choices: Anyone on Google+,
Extended Circles, Circles, or No One. Make your selection and then click
Save Changes at the bottom of the page.
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