Apparently there's something newish in the world of marketing. It's called "Voice Message Broadcasting" and no, we're not talking about telemarketers calling to pester you during your favorite evening meal. Vontoo voice messaging is a "permission based" system. That means that the people being contacted have chosen to "opt-in" to receive messages directed to their interests.
It's better than email in a lot of ways, not the least of which is the fact that email based marketing has been all but ruined by the insane level of spam that people receive each day. These voice messages aren't sent to people that haven't opted in and are much more likely to reach an interested party. This system is also easier to use and doesn't require additional software or hardware to be used.
One example of how this system has been used successfully is the case of a company in Georgia called "Great Frame Up". They had dozens of customers that had store credits they hadn't used. They used Vontoo to send a single voice message to 90 customers reminding them of their store credits that had not been used. This message brought a dozen customers in with framing work. This run of 90 calls brought a 300% return on investment. I am not a hamster but that sounds pretty good to me.