What's the difference between "Subscribers" and "Promoted" in the dashboard?
When people register onto your list they are put in the "subscribers" list. Optionally, you can "promote" them and put in a different list. But why would you want to do that?
Imagine you are hosting a competition where every week the top 5 on your list win a prize. Every week you want to reward these 5 people but also remove them from the list so that next week they won't win again.
If you want to send an automated email to the subscribers you promote, check the "Promoted email" in the "Engagement emails" tab.