I am an avid user of Khan Academy and I have found that Code Academy is similar to Khan. I really like the self-paced instruction and the step-by-step progression in learning how to code.

The best thing about Codecademy is that I can do use it from any device that has a web browser. That's an incredibly powerful tool to be able to pick up where I left off my self-learning from any device. I wanted to do some self study and learn some skills in back end web development, and Codecademy gave me a clear plan forward to learn what I wanted, without even asking a dime from me, unless I wanted additional resources to help me in my learning.

Honestly, the best thing about Codecademy is its interface. Having such a powerful learning tool baked into a web browser that can be accessed anywhere at any time is truly remarkable. I also love how many different languages are offered. I started using it to learn HTML/CSS, as I haven't dealt with that much due to my primary focus being on using C++/C# for Windows application development for work.