The CAN-SPAM Act of 2003 was passed by Congress as a direct response to the growing number of complaints over spam e-mails. Congress determined that the US government was showing an increased interest in the regulation of commercial electronic mail nationally, that those who send commercial e-mails should not mislead recipients over the source or content of them, and that all recipients of such emails have a right to decline them. The act authorizes a US $16,000 penalty per violation for spamming each individual recipient. However, it does not ban spam emailing outright, but imposes laws on using deceptive marketing methods through headings which are "materially false or misleading". In addition there are conditions which email marketers must meet in terms of their format, their content and labeling. As a result, many commercial email marketers within the United States utilize a service or special software to ensure compliance with the act. A variety of older systems exist that do not ensure compliance with the act. To comply with the act's regulation of commercial email, services also typically require users to authenticate their return address and include a valid physical address, provide a one-click unsubscribe feature, and prohibit importing lists of purchased addresses that may not have given valid permission.
When a subscriber is sorted into a segment, it can trigger an automation to send to them. Each person’s interactions with your email campaigns or your website can trigger a sequence of follow-up emails based on their interests, allowing you to hone your message to your targeted audience. For example, if someone visits your pricing page, you know they’re probably further down your sales funnel and will want to follow-up appropriately. Or if they went to a specific product page or clicked on a link for that product, you can send additional information about the product, testimonials and more.