has this method of collection been tried before? if not I'm guessing this is an untapped goldmine for the right entrepreneur: set up charities with simpler donation vectors.
I was more curious about the business of the middleman in this process, and I looked into it earlier today. This particular short code operator, mGive (http://www.mgive.com/) focuses on charities and was launched 2 years ago. I'm guessing this is their first big exposure.
Wikipedia has the basics of setting up a new short code: "Common short codes in the U.S. are administered by NeuStar, under a deal with Common Short Code Administration - CTIA. Short codes can be leased at the rate of $1000 a month for a selected code or $500 for a random code." (from http://en.wikipedia.org/wiki/Short_code)
It's about 2 years old. It's regulated by the Mobile Giving Foundation - http://mobilegiving.org/ The interesting thing here is that the carriers have agreed to pass your full donation amount to the charity, they don't take a cut.