CAN-SPAM stands for Controlling the Assault of Non-Solicited Pornography and Marketing Act. It's a law that mandates commercial e-mailers to clearly identify themselves and their products, provide working opt-out links, and honor opt-outs within 10 business days.
The act was signed into law by President George W. Bush on December 16, 2003, as Public Law Number 108-187.
CAN-SPAM applies to all commercial e-mail messages sent to U.S.-based recipients without their consent, regardless of whether they are solicited or unsolicited.
CAN-SPAM doesn't apply if the recipient has given prior express invitation or permission to receive communications from the sender; it doesn't apply if there is an existing business relationship (EBR) if the message doesn't include an advertisement or solicitation for a product or service (i.e., informational messages about noncommercial topics); and it doesn't apply if the message is sent from someone who has an existing relationship with you (i.e., personal messages from friends and family).