Beyond that, avoid using all caps, too many exclamation marks, and hyperbolic phrases ("ACT NOW BEFORE TIME RUNS OUT!!!!"). Poorly formatted HTML in your emails can also hurt how they’re handled. Every spam filter is different, so an email might pass through one filter but get flagged by another. For more comprehensive info on how spam filters work and how to avoid them, check out this guide by MailChimp.
What's the difference between them? One-off communications versus prolonged, email-based interactions. For example, email marketing tools are excellent for one-off communications. You can use these tools for the one time you'd like to send someone an automated email response when they join a subscriber list, on their birthday, or when you promote a new product. But marketing automation tools are better suited for prolonged, email-based interactions. For example, you can use marketing automation tools whenever you want to guide someone from a subscriber list to a product purchase. Or you can send thank you emails or send new product promotions—all without having to lift a finger after the workflow is designed.
Companies considering the use of an email marketing program must make sure that their program does not violate spam laws such as the United States' Controlling the Assault of Non-Solicited Pornography and Marketing Act (CAN-SPAM), the European Privacy and Electronic Communications Regulations 2003, or their Internet service provider's acceptable use policy.
Another way to extend the clicks on your email beyond its shelf life is to prompt your audience to forward the offer. The folks at Litmus found that the most forwarded emails were 13X more likely than the typical email to include “Share With Your Network” calls-to-action. By including forward-to-a-friend (or social sharing links, as we discussed above), you put it in recipients' minds to share.