CAN-SPAM defines a "commercial electronic 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)."
http://en.wikipedia.org/wiki/CAN-SPAM_Act_of_2003
a "commercial electronic mail message" leaves lots of leeway ....
just a matter of time before youtube spammers get sunk too ....