The Constant Contact Drupal module integrates features from the Constant Contact REST API into your drupal site, it's the only module you need if you use the constantcontact.com service and drupal.
You can place a signup checkbox or list selection on your register page or use the block to place a register form on any page or sidebar of your website.
Below are the main features provided in the module:
The module is free to use and can be downloaded from drupal.org
Please support this modules development, if you do not have a constant contact account signup for a free 60 day trial using this link