Mapping TED talks

This may be old news for many of you, but I've just watched this TED talk by Eric Berlow and Sean Gourley in which they analyze and visualize TED talks (that's very meta, isn't it)? I am posting a comment here because I like how they animated the data, particularly the transitions between network visualizations and bubble plots and maps.

Not surprisingly, being a TED talk, it is a bit too short and vague. It'd be great to learn more about the algorithms that they applied to analyze the content of the talks and their “mathematical structure.” I am curious.

(h/t Fernando Fiestas)