What should a blog be about?

I am still trying to decided where on the spectrum between free association writing and one very distinct formal topic (like references in the Count of Monte Cristo). Once I have a clue of a clue of a clue what I want to do with this blog I will post more. I am sure that it will change a lot between when I first start making actual posts and when I feel like I have it well enough defined to make it worth pushing out there for others to read.