Kurikku is a website that allows anybody to annotate code. In a sense it's like Rap Genius for code. You can use it to create tutorials and annotate it line by line or do code reviews to see how you can improve your code.
There are two customers, although we're only serving one right now. One is the software developer looking to improve their craft. The other are software companies looking to implement code reviews in their organization and need a tool for it.