Okay, It's pretty easy actually. If you are gonna dominate a keyword that have a lot of keywords under it ( the same keyword then it's a theme niche ). Theme niche always 2 words. It goes like this
Digital Camera ------>
- Cannon Digital Cameras
- Nikon Digital Cameras
- Best Digital Camera
- Cheap Digital Cameras
So you are in a theme- keyword. They all goes about digital cameras.
Micro Nich would be only one title of them
Cannon Digital Camer ---- > and you go through all the models
So the Theme-Niche would be a list of Micro Nich sites.
Digital Camera ---- > Cannon Digital Cameras ---- > Models of Cannon Digital Cameras
Broad Niche then we are talking about 1 word but specific. Like Camera and many theme-niche keywords under it
- Digital Camera , Kids Camera , Old Camera .............etc
And now u have a list of Niche Theme sites. And from each Niche theme site you have a list of Micro Niche Theme sites.
Finally , Comes the biggest one ( can't remember what he called it ) Anyway , A broad keyword which actually 1 word and have non related keywords under it.
Electronics would have ( camera , printer , mobile , laptop ........etc ) .
To Cover it up :-
Cnet.com & Pcworld.com ------- > best examples of broad-niche sites
GsmArena.com & Phonearena.com --- > Best examples in Theme-Niche sites
Of course the example here would be about affiliate site. For adsense site like the one in the book you gonna need informative niches not reviews one. Health as an Example or Insurance or Self-defense. Where ppl come for information more than a products.
Information for Adsense
Reviews for Affiliation
Hope this clear things up.
Gd Luck