Here would be my ultimate eMail contact service:
There are 3 types of mailings
One time broadcast, like announicing a sale for this weekend
Ongoing broadcasts, such as a newsletter (extra points for tieing it in with an RSS feed)
Autoresponder, sending a pre-written series of emails over a given time schedule
Recipients. Whether you call them separate lists or segments or whatever other terminology to break them down into smaller groups. For any given mailing, set which group(s) will receive that mailing and also make sure they only get it once if the recipient is in more than one of the selected groups.
When a person finishes an autoresponder series, there should be the ability to automatically add and/or move them to a different group(s). If you’ve left people in their original autoresponder group as well and you add a new mail to that series, those who have gone through the original series should also receive it … or a check box as to whether to or not.
Plenty of custom fields that can be evaluated at any time and be useable for creating a one time group on the fly as it were.
Split testing, tracking stats on opens, clicks, or whatever other metric you can think of.
Surveys and reponses
Direct or easilbly worked integration with at least the most common payment processors and content management systems.
HTML/plain text versions for each eMail. Automatically create the text version from the HTML but allow edits to it (or don’t use HTML at all)
Automatically breaking line length at a given column
Multi-media integration
Comments welcome as well as additions to the list of features it woudl be great if it had.






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