"That's a good question."
I believe that once I have an answer that satisfies me I will be as enchanted by, devoted to, and infatuated with blogging as I am by, to, and with twittering.
When you come right down to it (which is what I intend to do here after just a bit more beating about the bush) it's a question only you can answer.
It's your blog.
Blog about what pleases you in a way that pleases you.
And since what pleases me is to have the satisfaction of the sure knowledge that I have communicated with another (that would be you in this case) I have my answer in you! When you respond I know I have communicated. Although I realize that I may have communicated even though you do not respond, your response allows me actually to have the knowledge that I have been heard by another human being, that I have contributed something of value to another. I just love it when that happens.
I have my answer!
I am blogging to communicate.
I blog for the same reason I tweet.
For the same reason I write.
It is a vast distance from one human soul to another.