I think people blog for many different reasons, not all of them to do with being read or having the need to share publicly. For example, I have a couple of friends who use their private blogs to keep track of job applications and career planning - they find it gives a flexible platform for writing and storing information that can be easily accessed wherever they are. Another uses hers to store recipes. I'm toying with the idea of organising some of my favourite internet pages as private links on mine, so that they're readily available when I'm on a different pc, or my phone.

I did toy with keeping my blog entirely private, but have settled on sharing the address here and on my facebook profile, nowhere else at the moment.