How to design a content provider?

What are some great interaction design examples of search and browse for a library of learning content?  (Like the Boy Scout Merit Badge series...)

• We are building a library of content for the entry level employment market. The content chunks are analogous to a Boy Scout Merit badge.  A credential is awarded when the individual can demonstrate required competence.  A piece of content might be about Transportation and include an overview of transport modes, the importance of having reliable transportation for getting to work, and specific things people could do in the real world.  I would love suggestions from the community on the design and interaction pattern for people to find and browse this content with several high level categories, tens of subcategories, and hundreds of the smallest learning content.  I don't like pure search because we want people to see the landscape and discover elements.

• Answer:

  Check out Skillshare > Learn { http://www.skillshare.com/learn } Since their knowledge is class based, they likely don't have to organize and display as much content relative to a library. Still, they do a great job of structuring the class information (5 super-categories and ~40 subcategories) and making it pretty visual, scannable, flexible and approachable. Full disclosure: I haven't spent too much time with their keyword search or studying the information architecture. But it is still one of better examples I've come across.