Have you been to the site and watched a lecture?

There are comments of other students who watched that video. These comments are questions and answers about what was discussed. There are also links to exercises covering the content. Each lecture is arranged in a logical order for each topic. There are capabilities to integrate the video lectures and exercise with real-world classes and ways for teachers to track their students progress and the areas where each student is struggling is highlighted.

It's phenomenal and worth closer inspection if any of this is news to you.