So I was very interested in your site and signed up. Here are some of my first observations and comparisons:
- codecademy.com lists lots of males and females from young to old, from different countries with all kind of professions on their Success Stories pages. I felt very welcome their site. The name of your site and the constant use of the word Kata indicate to me that your audience are young males. As a woman in my thirties I don't feel I fit on your site. It seems a bit to aggressive to me.
- The second Javascript problem description was not very good. The second problem basically says "Something is wrong - correct it". I like clearer instructions like "write a function to reverse a string".
- Compared to codecademy.com the site took longer to check my code.
- I have no problem giving my e-mail address to anybody that provides a service I want to try. I like to get the onboarding mails from codecademy.com and think they should send out more because they are motivating. So I think that it is good that you are asking for my e-mail address and I hope you make good use of it by sending me interesting stuff. If not, I just filter you with a click.
I'm going to spend some time on your site. If you want further feedback, just send me a message.