Clay shirky has rocked my socks with some of his lastest writings. Basically if you want to have a popular blog it’s gotta be niche. In marketing traditionally it has been about bell curves i.e the majority being in the middle. With the internet this is not applying. It seems that it’s not balanced but completely unbalanced. 12% of the total blogs in the blogsphere (All the blogs) have 50% of the traffic. The number of subscribers to Yahoo groups is of the same graphical distribution.
My recommendation is get your blogs up and running now but also ensure that it’s niche or is really interesting to move the blogsphere audience to you.