If I'm not mistaken this original document was on Chico State's computer science domain. It was my understanding Beej went to Chico; does anyone know for sure? This was around long before 2006, I remember reading it around the year 2000 when I was first getting into C++. (miracle this quality of a document escaped anyone's brain in Chico -- I know, I went to CSUC. Let's just say it was hard to concentrate there :)
I also remember seeing this around the year 2000. (One giveaway that it's written in a previous century: It mentions SunOS. Not Solaris, but SunOS. When's the last time you heard somebody talk about that?) At that point I was already familiar with sockets, and mainly found the guide memorable because the name "Beej" had a weird sound to it.
Chico does sound familiar for some reason, with regard to this guide (I also recall reading it many years ago, probably a decade ago or more). I skimmed through it quickly for a version history but didn't see one.