Suppress - By Id: List of people exempted from the Campaign email. say for a campaign you have a default list of 100 targets of this list you do not want to send emails to 20 targets, first add these targets to a list of this type and then associate the list with the campaign.
Suppress - By Email Address: Same function as previous type. In this case exemption is based on email address comparison.
Suppress - By Domain: with this type you get an additional field "No emails to Domain", you can set a domain name in this field. say you want to suppress emails to <everybody>@yahoo.com, set yahoo in the domain field.
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