My guess is he's probably using a JavaScript library to provide text justification. It has some pretty great typography for a web page, hyphenation on the margin and all that. Fancy stuff. Some parts are way better than what CSS gives you.

Sucks that it doesn't show anything, but it's a bit ridiculous that 40 years after TeX we don't have proper typography on browsers and people have resort to stuff like this simply to justify text. Not that I agree with the choice, but I understand it.