I finished a few Codeacademy Courses and this is my feedback about this site.
In my oppinion the site dont really teach you to code it just give you a short insight into the languages and teach you the syntax. The main difference between learning coding in an university and here is that you dont have to use your brain here. The tasks are so simple and often already explained that you just have to copy from the left side.
This is not motivating, not fun and it wont teach you solving your own problems.
And problemsolving is the main skill that you need to practise if you want to code. Most of the time you dont do anything else then reading and then writing exactly the same stuff.
If you really want to teach someone coding you have to let people solve problems by them self. One of the better courses here is the Ruby course. Most of the chapters have some sort of summ-up-tasks where you have to remember what you learned and write this down out of your head.
Instead of showing exactly what the user has to write on the left side you should link a documentary page to teach the student to read and solve the problem like he would have to in the real world.
Dont get me wrong this site and it features are great but it could be alot more effective when you let the user more “room” to manage the tasks without holding his hand the whole time.