Quote from FTC:

“The new rule provisions address four topics:
(1) an e-mail recipient cannot be required to pay a fee, provide information other than his or her e-mail address and opt-out preferences, or take any steps other than sending a reply e-mail message or visiting a single Internet Web page to opt out of receiving future e-mail from a sender;
(2) the definition of “sender” was modified to make it easier to determine which of multiple parties advertising in a single e-mail message is responsible for complying with the Act’s opt-out requirements;
(3) a “sender” of commercial e-mail can include an accurately-registered post office box or private mailbox established under United States Postal Service regulations to satisfy the Act’s requirement that a commercial e-mail display a “valid physical postal address”; and
(4) a definition of the term “person” was added to clarify that CAN-SPAM’s obligations are not limited to natural persons.”

FTC CHANGES CAN SPAM ACT – RELEASE HERE:

http://ftc.gov/opa/2008/05/canspam.shtm

FULL DOCUMENT HERE

http://ftc.gov/os/2008/05/R411008frn.pdf