Using a Suppression List

When you Deploy a Normal Campaign, several options allow you to target contacts in your List.  To prevent messages from being sent to specific contacts, select ADVANCED OPTIONS and then choose a Suppression List. 

The campaign will send to all contacts in the List except those defined in the Suppression List.  The suppressed Contacts will remain subscribed to the List, but they will not receive the email message from the campaign.

At this time, there is no option to report which contacts were suppressed after a campaign.