The CAN SPAM act is an abbreviated form of the 'Controlling the Assault of Non-Solicited Pornography and Marketing Act” of 2003. It was signed into a law by U.S. President George W. Bush on December 16, 2003. The CAN SPAM act allows emailers to send marketing messages to email addresses without getting the owner's permission.

Therefore, the CAN SPAM act is applicable to any profit-making email ever sent. It is applicable to almost every professional who carries out his profession via the Internet, be it the web designer, the content writer or the affiliate marketer. The main requirements of the CAN SPAM act for commercial emailing are:

The subject line should not be deceptive about the contents of the email.

The email should not contain false or misleading routing information.

The CAN SPAM act defines the commercial electronic mail message. It defines a commercial mail message as any electronic mail message the primary purpose of which is the commercial advertisement or promotion of a commercial product or service (including content on an Internet website operated for a commercial purpose). This exempts transactional or relationship messages. The phrase 'primary purpose' was clarified by the FTC on December 16, 2004.

All profit making email should be identified as an advertisement; it should also include a valid physical postal address.

All commercial email should have the choice to opt out of the future mailings. The law therefore gives all commercial emailers ten days to discontinue the process of sending the emails to the specified email address.

The act also defines the act of sending sexually oriented emails without clear markings as a criminal activity.

Dictionary attacks are prohibited. Dictionary attacks mean a combination of letters, names and numbers in various permutations. Mails cannot be sent via open mail relays and hijacking computers through Trojan or worms.

Any email containing purely religious or political messages are exempted from the law. Messages pertaining to national security are also exempted from this law.

The CAN-SPAM Act has come under a lot of criticism by anti-spam activists. They very abbreviation is a play on the abbreviation of SPAM itself, with the positive 'can' attached to it. Anti-spam activists are of the opinion that the act gave spammers a federal approval to spam emails, provided they followed some rules and regulations, which could be easily broken via some loopholes. Even after this controversy in 2004, less than one percent of spammers complied with the rules of the CAN SPAM act.