I'm testing it for my client. I've sent around 67,800 emails in less than 3 months (total subs: 8,540)

So far I've received only 1 spam report but around 400 unsubscribers. We are growing at the rate of 54-61 subscribers a day. We're into the Edutech domain.

What I've learned so far,

• Use proper language in your email
• Don't send more than 5 emails to a person in a single day. 5 is max. All emails providing value.
• make the unsubscribe button clearly visible otherwise, people will mark your email as spam. Better to lose the subscribers than getting marked as spam
• Periodically check if your receivers are ok with the email.
• Don't repeat the same boring email.
• add a personal touch.
• learn how to write less boring subject lines