This is a wonderful start - kudos. If you're targeting beginners/novices, which it looks like you are, your current approach looks ideal. I wonder how this scales to more advanced topics/languages. I think there is a market (a much smaller market though) for advanced learning, and if done right a lot of beginners can be encourages to deepen/broaden their skills. Crowdsourced lessons, simplified to fit in with a successful learning framework like Khan Academy or Codeacademy.com is probably what will make this possible.
Any thoughts/plans to go that route?