Please note that your e-mail address will not be visible to a Google+ connectionunless you send or reply to that person with an e-mail. Similarly, that person's e-mail address is not visible to you unless they reply to you by e-mail.
Importantly, if someone outside of your Google+ circles sends you an email, you can decide whether you want to receive further emails from that person.

Domain administrators will have the option to control the availability of this feature through a new setting in the administrative part of the Google Apps Control Panel:

    Google Apps –> Configuración de Gmail –> Configuración de Usuario

If this feature is enabled in the admin console, users can control whether people outside their circles can reach them with this new setting in Gmail. It is possible to choose between:

• Any of Google+
• Extended circles
• Your circles
• Nobody

Important: The default setting will be: Anyone on Google+.