Unlike Raemon, I like the color scheme (Facebook made blue cool again). However, for me the site appears lacking in usability.

For example, I expected on the front page (or any other page) a number of terminal links you want people to click, say, in a column along the right side. By terminal I mean links to papers, ideas, examples, conclusions, not other collections of links. Each such terminal link should be a summary of what's inside. An extreme example of this approach (which works well in news media) is The Register.

There is also very little use of mouseover menu expansion ("what would happen if I clicked on...?" without actually clicking). While it can be distracting and annoying when done badly, it's practically expected from a modern site.

The use of PDFs as the only document format, to me, greatly detracts from usability, because it is harder to navigate than HTML, slower to download and in some cases (e.g. mobile) requires a separate application. PDF should be an option for those who like pretty formatting for printing and reading offline.

We’ve made hundreds of minor corrections to our past papers, and ported them to a new PDF template that is easy to read and unusually functional.

I presume that it is only "unusually functional" for those who use Adobe Reader.

I hope you are doing some A/B testing with this page. If not, you ought to.