This seems awesome to me as well but I don't want to sign up without learning more. Who are the teachers? How does it work? Does it cost anything? etc.
Actually there are no human teachers, the lessons are interactive and automated much like Codecademy. You're shown a few notes at a time and then as you play, the software detects each note and gives you feedback. There's also a virtual guitar mode so you can try it out without a guitar (it does require a signup though, at least for now).
That's good info - you need to have a "How it works" page rather than ask for the details before you share that. I love the idea though!