This one is interesting because it's an active number that is not spoofed.  I just received calls from this number to both my office line and my cell phone about a minute apart.

It's definitely a robodialer, because nobody responds when I said hello.  After not finding it on 800Notes, I called it and it was answered by what sounded like an automated male voice, saying something like yeah...you dialed the wrong number, you idiots, followed by the voicemail box is full.

I would have to say it's a different approach to phishing for active numbers to sell.