There are multiple ways you can use your e-mail marketing campaigns, two of them are e-mail newsletters and e-mail promotions. However, the purpose behind e-mail newsletters (customer retention) is drastically different from e-mail promotions (customer acquisition).
E-mail promotions are for immediate action, whether it be prompting a purchase, downloads, or sign-ups. E-mail promotions generally have a short-term value that require response within a specific time period. These e-mails are for immediate returns.
On the other hand, e-mail newsletters deal with building long-term relationships with your clients and customers. By building a relationship, the readers of the newsletters will be more likely to take an action in the future.
If you send e-mail promotions to people who want newsletters, you’ll end up with a low response rate and high unsubscribe rate. The subscribers weren’t interested in constant promotions about your company. Sending promotional emails to email newsletter subscribers is less effective then sending newsletters to newsletter subscribers or sending promotional emails to those who opted in for explicit promotions.