It's also strange they say using var is good practice but then don't put ; at the end of lines. It seems like they have the basics really nailed but need a few other people to review their material.
I'm going to be e-mailing them a mail with a few of my suggestions.
I'd love to see this go further. Their app is a great place for people to learn in.
As with all educational material, it's a trade-off between simplifying things for the beginner, and being totally correct. (Kind of like how in physics, you learn mechanics, and then find out it's not totally correct.)
I know a number of people who taught Java by starting teaching the basics of programming within a class (e.g primitives, functions, etc) but neglecting the class wrappings. This teaches people procedural programming. They then have to unlearn in order to do OO.
Teaching them the basics while asking them to put up with the "framework" means that they aren't unlearning, they gain knowledge of the "stuff" they were putting up with.
Direct link: http://appjet.com/learn-to-program/
Update: I love how step 5 gets you to send emails. That would be like step 100 in most other frameworks.