Niche Guide10 Jan 2007 04:41 am
Just because a sub-niche is popular doesn’t mean people spend money on it.
Amazon – http://www.amazon.com
Amazon is a great place to see what currently exists for any given sub-niche.
Chances are, the more books there are written on that subject, the more that market spends on those topics.
For example:

First I specify “Books” to search. Then I enter my niche, in this case “crafts.”
Uh oh. There are WAY too many books returned. This niche is not targeted enough. It is too “mainstream.”

Much better! There are possibilities here.
We now suspect the following:
1) This sub-niche may be targeted enough.
2) This sub-niche may spend money.