In a previous life as a network admin, I took all sorts of certification tests — A+, Network+, I-Net+, CNA, and MCP, which I later upgraded to MCSA and then MCSE.
One thing that these tests always required was extensive knowledge of obscure parts of a technology regardless of their usefulness in working with the technology. You have to know all sorts of useless information to officially be an expert.
Since I’m studying for the Microsoft .NET Framework Foundation (70-536) exam, I’ve been investigating the cobwebbed corners of the framework. It’s amazing how many things there are that I’ve never used, never thought I’d use, and probably never will use. Even so, I have picked up a few useful tricks in the process.
What doesn’t help is the extensive amount of errata in the thousand-plus-page study guide. There’s so much broken that there are FOUR knowledge base articles, presumably due to some sort of size limitation in a KB article:
http://support.microsoft.com/kb/923018
http://support.microsoft.com/kb/935218
http://support.microsoft.com/kb/949730
http://support.microsoft.com/kb/949734
Needless to say, I’m not relying too heavily on a single reference book.