[troygoode]

> Where is the line between something like MailChimp and Courier?

Mailchimp has two services: a marketing tool for e.g. newsletters and a transaction email service (previously called Mandrill). Most customers use Courier alongside marketing tools like Mailchimp's newsletter tools - we're more for your active users, not marketing to potential users.

We do integration with Mandrill / Mailchimp Transactional to add our orchestration, preference management, routing, templating, etc. tools so that you don't have to build those yourself on top of their pipes.