Can't Understand It? Don't Worry.
Whenever somebody gives you a spec for some new technology, if you can't understand the spec, don't worry too much. Nobody else is going to understand it, either, and it's probably not going to be important. This is the lesson of SGML, which hardly anyone used, until Tim Berners-Lee dumbed it down dramatically and suddenly people understood it. For the same reason he simplified the file transfer protocol, creating HTTP to replace FTP.
You can see this phenomenon all over the place; even within a given technology some things are easy enough to figure out and people use them (like COM's IUnknown), while others are so morbidly complicated (IMonikers) when they should be simple (what's wrong with URLs?) that they languish.
You’re reading Joel on Software, stuffed with years and years of completely raving mad articles about software development, managing software teams, designing user interfaces, running successful software companies, and rubber duckies.