From the list of all Contacts it is possible to filer by 'status' of 'Double-Opt-In'.
Contacts who have 'double-opted-in' are those who have actively clicked on a 'double-opt-in' link from one of your mail shots. You may chose to only email contacts who have opted in using this preference to satisfy and internal or external compliance request.
To learn more about adding 'double-opt-in' links please visit the mail shot custom links page.
Please Note: The use of the double-opt-in functionality is entirely optional.