I built https://www.findlectures.com, which is categorized list of lectures and speakers, inspired by the faceted search on Newegg and Amazon, which I wish Youtube had.
It's been a fun project, because I've had to build tools to come up with a lot of quality measures for the dataset.
I'm working toward custom entity recognition, which would help in that area. For instance, listing all lectures about a particular programming language, lectures on the history of countries that no longer exist, etc.
