Our friend Lev Tsypin at ThinkShout has just put the finishing touches on a complete rewrite of the Drupal module for MailChimp. It has a completely redesigned interface with a lot of fundamental changes under the hood to make use of some of the new goodies that Drupal 7 provides.
This module allows developers to integrate a slew of MailChimp stuff into Drupal applications with minimal effort. For example, you can quickly create signup forms and synchronize your registered users in your app to a MailChimp list.
One of the features that make this redesign so cool is the new integration with our STS Service. This means that you can contain all of your Drupal App’s email (both transactional email and your bulk email) to MailChimp. It also provides delivery reporting so that you can have some insight as to where your transactional email is ending up.