I think he's experimenting with linking to other documents. I did something similar as an experiment (http://www.conman.org/people/spc/writings/hypertext/fragm

I think he's experimenting with linking to other documents. I did something similar as an experiment (http://www.conman.org/people/spc/writings/hypertext/fragment/ http://www.conman.org/people/spc/writings/hypertext/fragment...) but ended up just sticking with the default underlines.