[manglav]

To be clear, the market is already a niche (Taskrabbit, AirBnB, LawPivot, etc). I was advising you to find a smaller segment of the market to start from. This should be something you're familiar with, and should have a decent concentration of said niche. For example, I don't advise trying match Eskimos with Popsicles that they want (not enough volume). Finding "your niche" is sort of easy, try graphing your time weekly and see what activities you do. Then rank your activities based on the strength you have in them. The top one is your best niche to attack in your local market.

Pinterest pulled a Steve Jobs - it was their job to know what consumer's wanted a year in the future. They were able to see that the coming smartphone explosion would combine with people wanting to be social, and what evokes a lot of emotion? Looking at old photos with friends. Add some filters on top to hide any bad picture taking skills/catering to the masses, and you have a billion dollar idea. They also provided a billion dollar execution, by exiting within two years. Pinterest was a case when all the stars align in the startup universe, and they also worked really really hard to build the telescope to see them.