What are the key requirements under CAN-SPAM for commercial email?

CAN-SPAM (Controlling the Assault of Non-Solicited Pornography And Marketing Act) applies to commercial email sent to US recipients:
1. Honest From header: The From name and address must accurately identify the sender.
2. Honest subject line: Must not be deceptive or misleading about the email's contents.
3. Physical address: A valid postal address (or PO box) of the sending organisation must be included in the email body.
4. Opt-out mechanism: A clear and conspicuous way for recipients to unsubscribe must be present in every commercial email.
5. Honour opt-outs within 10 business days: Unsubscribe requests must be processed within 10 business days; you cannot require the subscriber to pay a fee or provide information beyond their email address.
6. Transactional exemption: Transactional emails (order confirmations, password resets) are largely exempt from CAN-SPAM requirements but must still not be deceptive.