There are a number of similarities. Khan's working on making a very slick tool with a really nice interface to let people experiment with coding.

The focus of CodeHS is much more on the instruction from teachers, and it has more structure. We have tutors that give debugging help and feedback on all programming exercises and projects, so you learn much more about programming style in addition to functionality.

I think Khan has a cool tool, but it's only a tool, whereas we're giving the entire learning experience, teacher included.