In its efforts to popularize Google+, Google has just announced a new feature: very soon, you can send messages to service users from Gmail, even if you do not know the address of email for each of them.
The idea is that as the user is typing a name in the e-mail recipient field, Gmail automatically go suggesting people on Google+. The message will be delivered to the chosen name (will appear in the “Social” Gmail, for those who have this feature enabled), but you can only discover his or her address if the person responding to the contact.
It is likely that most users adopt the new, but certainly there will be those who will be concerned about your privacy, so, Google tried to warn you right now that you can configure the operating mode feature.
In this sense, users can allow the suggestion of your profile to appear to anyone, only for those in your circles, just for these contacts and friends, or those who want to radicalize, to anyone.
Google promises to make the news for all users in the coming days, gradually. You will receive an email with instructions and a link configuration when your account is contemplated.