Building A Web Directory? Resources?

Lately I have been pretty obsessed with the idea of building a web directory related to my niche.

After all isn’t this the way the guys at Yahoo got started?

Can anybody recommend any resources to study for this type of project?
Are there any out there? Any good ebooks to recommend on this?

It seems that the spiders love the directories and if the directories are done correctly they can be great traffic centers and generators.

I have been compiling a list of of some of my favorite directories and I often visit them and study their structure. Some are pretty amazing works of programming!

Anyway, I would appreciate any ideas that y’all might have.

Thought I’d ask some of the EXPERTS first before I start building and realize that I have completely overlooked something important.