I write my blog for me. I put stuff there, so I can have easy online access to it, and so that I don't forget it, or have to google it again. It varies from pretty basic stuff, to some step-by-step tutorials.

The benefit for me is that I have it when I need it. Oh, and a nice ego bust when I write a new blog post and see ~100 to 200 daily visits for a few days before the external traffic dies out.