Subject: The website will be down at 5pm for 5 minutes EOM
Putting EOM at the end of the message in the subject line indicates that it is the END OF MESSAGE.
This is useful because it provides the recipient with quick and relevant information without the need to open the email because the entire message is contained in the subject.
Additionally, the person sending the email will avoid the 'Send this message without text in the body?' prompt because most programs recognize the EOM command.