When you send an email message, you can choose to automatically save a copy of the message in the Sent folder.
To activate saving copies of sent mail:
Any time you'd like to stop saving your sent messages, return to the General options page and deselect the "Save a copy of the message in the Sent folder" checkbox, then click the Save button.
Messages in your Sent folder display the names of those to whom the messages were sent, rather than the name of the sender. If a message in your Sent folder is marked as unread, it is because you yourself have not opened it; this is not an indication of whether the recipient has received or read the message.
Note: Messages cannot be moved into the Sent folder from other folders. Once a message has been moved out of the Sent folder, it cannot be moved back in.