Interesting question and no doubt one that's been discussed before. Most 'gurus' or im ebooks recommend finding a niche when starting an online business. In fact, terms like micro niches and mini niches are becoming popular as people narrow down their target audience to a few hundred targetted searches per month. The thinking behind this seems quite logical. Find markets that are unsaturated, build small sites related to this niche and if you build enough of these sites it adds up to a decent income. While I started doing this, I tend to move toward the larger site model now. For example if I find a niche for say dog collars, in the past I would have created a site that just sold dog collars but now I would create a pet accessories site but focus a lot of the optimisation on the dog collars section. I also don't shy away from mainstream topics like celebrities and news. In the past I thought I would never rank for these, however Im finding that brand new blogs with 0 pagerank and few inbound links are getting several hundred visitors a day unlike my niche, optimised sites. What's your vote? Niche or not?