For the past years, it is becoming more and more accessible to get college level content from many different sources, and, if one is willing can get very far with his math education (not only by watching video classes, but by using sites like this, etc) using online resources.
But what I feel lacking are online resources to get someone to be very good at Math on a High School level. Why there is not some MOOC to teach high school Math concepts? Why there is not other courses?
If you could devise a whole High School Math curricula to be available online, how would you shape it?
I know that it is a far broad question, but I do hope that it is not off-topic.