The CAN-SPAM Act, which stands for Controlling the Assault of Non-Solicited Pornography And Marketing Act, is a law enacted in the United States in 2003 to regulate commercial email messages. Its main purpose is to set standards and requirements for sending commercial emails, as well as providing recipients with certain rights and protections.

Under the CAN-SPAM Act, commercial emails must include accurate header information, clearly identify themselves as advertisements, provide a valid physical postal address of the sender, and offer recipients a clear and easy way to opt-out of future emails. It also prohibits the use of deceptive subject lines and false or misleading information in the email content.

The Act requires that opt-out requests from recipients be honored promptly, usually within 10 business days. Once a recipient opts out, the sender is prohibited from sending them any further commercial emails, unless the recipient explicitly opts back in.

In addition to regulating commercial emails, the CAN-SPAM Act also prohibits certain practices related to email harvesting, such as using automated software to collect email addresses from websites without permission. It also prohibits sending emails to harvested email lists or using false or misleading information to obtain email addresses.

Violations of the CAN-SPAM Act can result in significant penalties, including fines and imprisonment.