The new rules cover commercial messages sent to mobiles that use email addresses provided by cellular carriers. The rules do not cover SMS spam, and do not appear to cover instant messaging spam.

The Commission unanimously adopted a general prohibition on sending commercial messages to any address referencing an internet domain associated with wireless subscriber messaging services.

The FCC said in a statement that: The establishment of a list of domain names appeared to be the most effective method to allow subscribers to avoid unwanted mobile service commercial messages.

Cellular carriers will have to provide the names of the domains that they use in subscriber messaging services. Any spam sent to addresses at those domains will be covered by the regulations. Messages sent to phone numbers are not covered.

The FCC found that Short Message Service messages transmitted solely to phone numbers (as opposed to those sent to addresses with references to Internet domains) are not covered by these protections.

The Commission added that existing junk fax laws that ban autodialed commercial faxing cover SMS spam, if it uses autodialers. SMS, unlike email spam, does put a per-spam cost on the spammer, which could be a barrier to entry.

The Federal Trade Commission is tasked with deciding what is and is not a commercial message, as opposed to a transactional message. Commercial messages can be sent to people who have opted to receive them in writing, electronically, or orally.

Commissioner Michael Copps said: My only hesitation here is our decision to allow companies to obtain opt-in approvals that are not in writing. Oral approvals are harder to verify and may pose problems for us in the future. We’ll need to monitor that.

FCC chairman Michael Powell said the regulation strikes an effective balance between protecting consumers from unwanted messages while minimizing the burdens on senders of such messages.