I'm in teaching business (teaching seo to people). So I choose SEO as my niche. Then affiliation. Earn a lot out of those two. Earned something from Loan also. (I had ads on cl). Nowadays no ads so no profits from this niche.
I've always been interested in job search niches, classified niches, etc. People will never stop being interested in those things.
Our website niches are in Web Tools Directory, since when we started to look for web tools, we could not find any encouraging site that had a combination of Google,Yahoo, Windows etc. web tools.
I believe the niche should be chosen on the principle of supply and demand. In other words, if there's no demand for something, then that niche will be either dead or very slow. Or if there's a demand, but there are too many suppliers then the competition will be tough. That's why it's recommended to try out several niches to find out where the most demand is and then work on improving that one or maybe two niches.
PatriotBarter was started because of a lack of barter oriented classifieds that didn't have a lot of restrictions like no firearms, ammunition, etc.
I'm surprised so many people are opening up! My niche isn't too competitive so I'm keeping quiet for now
I try to pick my niches in only those three areas: money health relationships but by association of ideas I can mix one idea and another while still keeping within one of those 3 topics.
One niche I am in is about business ideas. I've not been too successful with it. But, I've had a little bit of success with it.
I have business consulting, IT project management, business development and business help niche and hope to go well in the future.