Email is the most productive promotional channel with an average ROI of 145%. Sellthrough has written multiple ebooks on how to make progress on this over the years, focusing on techniques like personalization and behavior-based trigger messages. However, your email marketing program will only have a significant impact on your brand's bottom line if your messages are actually received. Many marketers don't realize that deliverability and revenue have a much more symbiotic relationship. Consistently, people receive more than 300 billion messages, which is 0.02% of the message volume actually sent. Concerned with securing clients' inboxes as a matter of first importance, Internet Service Providers (ISPs) identify most messages as malicious spam, blocking them out and out. ISPs rule on caution and cast a wide net, giving comparable treatment to any email that appears to resemble spam. As indicated by Return Path's 2018 Deliverability Benchmark Report, the typical inbox pla...