The CAN-SPAM Act, a law that sets the rules for commercial email, establishes requirements for commercial messages, gives recipients the right to have you stop emailing them (opt out or unsubscribe), and spells out tough penalties for violations. Despite its name, the CAN-SPAM Act doesn’t apply just to bulk email. It covers all commercial messages, which the law defines as “any electronic mail message the primary purpose of which is the commercial advertisement or promotion of a commercial product or service,” including email that promotes content on commercial websites. The law makes no exception for business-to-business email. That means all email – for example, a message to former customers announcing a new product line – must comply with the law.