Settings. It needs to be made clearer, imho, as it's a mistake many can make, unwittingly
Since the release of the latest mobile software Android 4.4, codenamed KitKat, the instant messaging app Hangouts has become the default text-messaging app on phones and tablets running with the newly installed operating system.
But the behaviour of the app is confusing even to seasoned Android users, and can result in personal information being inadvertently shared. If a message is sent as an SMS, the recipient only sees the phone number it came from, but if it is sent as a Google message, then they can see the sender's entire public Google profile.
In at least one instance, this has already caused serious problems. A trans woman, still using her old (male) name at work, intended to send a text message to a colleague. Instead, she sent a GChat message under the female name on her Google+ account.
"I'm just glad I live in a state where it'd be illegal to fire me," said the woman, who asked not to be named in this piece while she discusses matters with her employers. "Somehow I didn't think through the potential consequences of Google+ embedding itself ever deeper into stock Android stuff."Google+ and Android Integration Reveals Personal Identity By Default [theguardian.com]