an advertisement that you run usually through an ezine
an email with only one paid ad
an independent, single email advertisement you can
a short advertisement that is sent to the complete subscriber list of an ezine or mailing list
a special offer or information about a product or service emailed to opt-in subscribers of ezines or online publications
This is an ad that goes out to all the subscriber's of a newsletter or ezine. It is sent out separately from the newsletter.