

The message might be indexed by local search engines and may show up at other times. All it takes is a click or two to read the entire contents, regardless of whether the email was intended for someone’s eyes or not. On a shared computer or tablet, the email might download automatically via clients like Apple Mail. Even on a mobile device that’s locked, this can give away information to anyone looking over the recipient’s shoulder. This usually takes the form of a push notification with a visible subject line and a preview of the message contents. The server can see the entire contents of the email, and any devices set up for use with that email address can notify the recipient of a new message.

When you send an email to a standard webmail address like Gmail, the server receives the email and notifies the recipient.
