If I ever find out what Project Xanadu's default color scheme was supposed to be, then I will probably switch a web site to it. In loving memory of a future that we exceeded and still failed to live up to.

(Xanadu was the first idea of a hypertext system. It was more heavyweight than the current system, which may be why it never caught on -- but it was incredibly visionary. Sometimes I read futurist writing from that time, and I'm struck by how much better we've done and by how much of its early promise we have left unfulfilled.)

http://en.wikipedia.org/wiki/Project_Xanadu

And in case others missed the point, his site isn't that color in some kind of tribute...his site is that color because he's jwz, and he wrote vast swathes of Mozilla, and he can make his website any color he wants.