The most common user interface to a standard treeware book, I would hypothesize, is to read through the book linearly. More sophisticated approaches to reading a book flow from more sophisticated information needs, which is where tables of contents and indices start to be useful. My guess is that as users start to make more sophisticated use of the content available at this site, and as the content of the site becomes more elaborate, the metadata will become more and more valuable.

I'm still struggling to get used to the concept of the web structured with metadata, so I didn't even know your index (called "Subjects") existed, but now that I've seen it, I can definitely invision it being useful. I don't expect (or need) an index in a novel, but I use one extensively in a math reference; I haven't expected (or often, needed) useful metadata artifacts to aid me in browsing the web, but I look forward to utilizing them as they emerge.

As a RFE, it would be a nice user interface accessibility addition to provide a "jump to letter within the page" table at the top of the page. Do you want feedback like this posted within comments, or mailed directly to you?

Thanks for the RFE. Digging around in that code turned up some bugs which I've fixed along with providing the links into the content.

RFEs are probably better sent by email, but here is ok, too.