About CAN-SPAM Act of 2003
The CAN-SPAM Act of 2003(Controlling the Assault of Non-Solicited Pornography and Marketing Act) establishes requirements for those who send commercial email. The law, which became effective January 1, 2004, covers email whose primary purpose is advertising or promoting a commercial product or service, including content on a Web site. A 'transactional or relationship message' email that facilitates an agreed-upon transaction or updates a customer in an existing business relationship - may not contain false or misleading routing information, but otherwise is exempt from most provisions of the CAN-SPAM Act.
The law says the sender must provide a return email address or another Internet-based response mechanism that allows a recipient to ask the sender not to send future email messages to that email address, and the sender must honour the requests. The law requires that commercial email be identified as an advertisement and include the sender's valid physical postal address.
If the emails you are receiving are commercial in nature, they should contain opt-out mechanisms. If you receive a regular mailing, like a newsletter, the sender should have Unsubscribe information available at the registration site.