You have to click on the bold links to "drill-down". So, if you click on "johann sebastian bach", it will give start to give you results such as: "Vivaldi's Cello" and "History of Germany"

Currently, we're limited to running on one server. Therefore, the algorithm is restricted to running on the english Wikipedia corpus.

It appears that the "skip slope" metaphor with the shapes was a bad idea.

Each shape is a ski-slope difficulty rating symbol. So, Green -- "easy" -- will take the meaning of your query more literally. Double black diamond -- "advanced expert" -- will try to extrapolate hidden meanings in your query. It will suggest topics that are less obviously related to your query.