Because the CAN-SPAM Act of 2003 authorizes a USD 11,000 penalty per violation for spamming each individual recipient, many commercial email marketers within the United States utilize a service or special software that helps ensure compliance with the Act. A variety of older systems exist which do not ensure compliance with the Act. To comply with the Act’s regulation of commercial email, services 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 which may not have given valid permission.

In addition to satisfying legal requirements, service providers stepped in to help customers to set up and manage their own email marketing campaigns. The services provide email templates, automatically handle subscriptions and removals, and generate statistics on how many messages were received and openned, and whether the recipients clicked on any links within the messages.