This is actually a lot easier if you have a specific niche as per your example. Without a niche, the whole world is your target and you will not have any good

This is actually a lot easier if you have a specific niche as per your example. Without a niche, the whole world is your target and you will not have any good place to market to. With a niche you are able to clearly say that you have a target market and then constrain your activities to just attracting them. When I started a fixed gear cycling forum I didn't really know anyone, so I spent time researching where they hung out, and understand the problems with the tools that they already used. When I finally pitched my product to them it was by then as a friend rather than a cold-call, and they already knew me and I they... it wasn't enough to make revenue on day one, but it was the start of a snowball effect as they each invited others. Niches are good. If you have one look to where those people already hang out... in the real world as well as virtually.