Danny Dover at SEOmoz recently posted a fascinating article on the state of blogs. There are great stats on who controls the top blogs as well as the gender breakdown and audience profile for high traffic blogs.
One of the key takeaways is that there is still a lot of room for growth, especially in non-Technology topics. In addition, there is a huge opportunity to develop new blogs targeted at women. The key here is to find a niche and develop a new audience in a unsaturated market.
Inspired bloggers out there can then use tools like HitTail to determine what are the hot topics people are interested in within a particular niche that will drive traffic to their blog.