Coming soon to a phone near you
SPAM!

I have been predicting that with the rise of Voip and the easy integration of the phone network with computers, it's only a matter of time before you get ads for V1agra and C1a11Is in your voicemail.

Well, yesterday, that happened to me! I received a phone call from a spammer. I answered the phone and there was a recording selling me information on how to lower my mortgage rate!

Essentially if you can get access to a SIP connection to the phone networks, you can initiate as many phone calls as you have bandwidth for and spoof the caller-ID as well. That sounds a lot like how SMTP works....

Update:

From U.S. Code Title 47:

§ 64.1200 Delivery restrictions.
(a) No person may:

(1) Initiate any telephone call (other than a call made for emergency purposes or made with the prior express consent of the called party) using an automatic telephone dialing system or an artificial or prerecorded voice,
(i) To any emergency telephone line, including any 911 line and any emergency line of a hospital, medical physician or service office, health care facility, poison control center, or fire protection or law enforcement agency;
(ii) To the telephone line of any guest room or patient room of a hospital, health care facility, elderly home, or similar establishment; or
(iii) To any telephone number assigned to a paging service, cellular telephone service, specialized mobile radio service, or other radio common carrier service, or any service for which the called party is charged for the call;

(2) Initiate any telephone call to any residential telephone line using an artificial or prerecorded voice to deliver a message without the prior express consent of the called party, unless the call is initiated for emergency purposes or is exempted by § 64.1200(c) of this section.