I love the idea (and simplicity of it) but isn't this basically forwarding each scheduled message to follow up service? Seems like a little too much trust involved for me.
The developer claims that it takes only 5 minutes to set up, and you can get a micro AWS instance for free. Then you control all the data, and you don't have to pay.
Quick shameless plug, this was a weekend project and it's up on Github, just PHP and MySQL, so if anyone wants to contribute it is more than welcome.