When u look at any internet marketing website/board u get slapped by niche, niche, niche what do you consider a niche regarding: google competition overture search number I go for a niche when there are about 1000 searches a month and less then 500.000 competitive pages in google. It also depends on the seo done to the top 10 sites and the backlinks to them offcourse
It goes by subject matter more than anything. If you have something good, traffic will increase as your popularity does.
Prime example is my rugby forum. Is it niche? YEp, but there are also niches within it. eg Rugby has two codes union and league, we are league. Rugby is played around the world, but my forum is predominantly a Welsh & UK rugby site. Pets is a niche, but dogs are a niche within that, A breed of dog is a niche again. German Shepherd for example. German shepherd health and handling is a niche within that also. Do you see how niches work now?