Messages that are identified as spam are sent via the ProofPoint email protection server to your personal Spam Quarantine and an End User Digest email message will be sent to in your mailbox. The Digest provides you with a list of the messages addressed to you that are stored in the Quarantine. You can look at the message subject headers to determine their content and decide what actions you want to apply to the messages.  

You may also receive an empty Digest, which is simply an email message indicating that you have no messages in the Quarantine. You may want to receive a Digest even if it doesn’t contain any messages, so you can continue to manage certain aspects of your email. The system administrator decides whether or not users should receive an empty Digest.