What do you think about launching products in small niche markets and making money with it?

Personally, I've had great success launching niche products and marketing them. There's a three step formula (if you say that) - that'll work well. Generally, people go for niche with competition, because there is money to be made, that's why there is competition.

With niche marketing, we target niche with less competition and completely dominate the market. I came to know this through the Underachiever formula... (Frank Kern)..

What are your thoughts... ever done this?