CAN-SPAM Act – An often misunderstood law, this act relates to US standards established in 2003 regulating commercial email. Enforced by the FTC. Boiled down, as long as you follow the rules of email content, permission is not a necessary component under the law. See more here – Wiki CAN SPAM Act
Cold List – Individuals who may have expressed interest in your product or service, but who have not expressly opted in or subscribed to your list.
Warm List – This refers to contacts who have expressly opted in or subscribed to your list.