The most advanced email marketing services offer custom workflows where you can specify triggers based on actions (such as opening an email or making a purchase) or on inaction (such as ignoring emails). With these services, you can also set up a series of emails (such as tutorials) to be sent to segments of users, and you can pause or stop a campaign at any time. You can also move contacts into new segments once they have completed tutorials.
Infusionsoft is a fully functional CRM and marketing solution created for small and medium-size businesses. Comparing it to Mailchimp or AWeber is like comparing a Lamborghini to a VW Golf. It provides highly advanced features for list segmentation, lead scoring, and marketing automation. On top of all that, you can integrate all of these features with your optin form using Infusionsoft Tags + OptinMonster.