What a brilliant idea! Deliver an online course to a learner’s inbox one lesson at a time. At the end of each lesson simply click a link to trigger delivery of subsequent lessons. If learners lose track or interest you can trigger occasional reminders and you can even tie in ecommerce if you want to charge for your course
This can all be done using MailChimp. The author walks you through the MailChimp configuration process step-by-step which really amounts to calling up integrated event triggers.